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LSU Historical Dissertations and Theses
Graduate School
1965
A Study of the Inheritance of Root Shape, Skin
Color, Total Carotenoid Pigments, Dry Matter,
Fiber and Baking Quality in the Sweet Potato
(Ipomoea Batatas).
Harrell Lee Hammett
Louisiana State University and Agricultural & Mechanical College
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Recommended Citation
Hammett, Harrell Lee, "A Study of the Inheritance of Root Shape, Skin Color, Total Carotenoid Pigments, Dry Matter, Fiber and
Baking Quality in the Sweet Potato (Ipomoea Batatas)." (1965). LSU Historical Dissertations and Theses. 1076.
http://digitalcommons.lsu.edu/gradschool_disstheses/1076
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~
H AM M ETT, H a r r e ll L e e , 1 9 2 5 A STUDY OF THE INHERITANCE OF ROOT
SH A PE, SKIN COLOR, TO TAL CAROTENOID
PIGM ENTS, DRY M A TTER , FIB E R AND BAK­
ING Q UALITY IN THE SWEET POTATO
(IPOMOEA BATATAS).
L o u isia n a State U n iv e r sity , P h .D ., 1965
A g r ic u ltu r e , plant cu ltu re
University Microfilms, Inc., Ann Arbor, M ichigan
A STUDY OF THE INHERITANCE OF ROOT SHAPE, SKIN COLOR, TOTAL
CAROTENOID PIGMENTS, DRY MATTER, FIBER AND BAKING
QUALITY IN THE SWEET POTATO ( IPOMOEA BATATAS)
A Dissertation
Submitted to the Graduate Faculty o f the
Louisiana S t a t e U n i v e r s i t y and
A g r i c u l t u r a l and Mechanical College
in p a r t i a l f u l f i l l m e n t of the
requirements f o r the degree o f
Doctor o f Philosophy
in
The Department o f H o r t i c u l t u r e
by
H a r r e l l Lee Hammett
B . S . , Louisiana P o ly t e c h n ic I n s t i t u t e , 1951
M . S . , Louisiana S t a t e U n i v e r s i t y , 1953
August, 1965
ACKNOWLEDGEMENTS
The au th or wishes to express his a p p r e c i a t i o n t o each member of
the committee f o r ad v ic e , c r i t i c i s m s and encouragement.
p e c ia lly grateful
to Dr.
He is es­
J u l i a n C. M i l l e r and Dr. C. C. S i n g l e t a r y f o r
making the f a c i l i t i e s o f the Department o f H o r t i c u l t u r e a t Louisiana
S t a t e U n i v e r s i t y and M i s s is s ip p i S t a t e U n i v e r s i t y ,
a v a i l a b l e f o r t h i s study.
G r a ti tu d e
respectively,
is extended to Dr. Teme P.
Hernandez f o r d i r e c t i n g the problem and c r i t i z i n g
the manuscript; to
Dr. M. T. Henderson f o r counsel and f o r c r i t i z i n g the manuscript; and
to o t h e r members of the committee f o r re vie wing the manuscript and
o f f e r i n g suggestions.
A p p r e c i a ti o n
is expressed to Dr. E. L. Moore
and Dr. J. B. Edmond f o r advice and a s s is ta nc e
script,
and t o Dr. W. J.
in preparing the manu­
Drapala f o r his as si st anc e w it h the s t a t i s t i ­
cal an alyses.
To his w i f e ,
Emma Lee B. Hammett, and f a m i l y ,
the w r i t e r expresses
his g r a t i t u d e f o r t h e i r s a c r i f i c e s which made t h i s study p o s si b le .
TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS..............................................................................................................
ti
LIST OF TABLES......................................................................................
iv
LIST OF PLATES.................................................................................................................. vi i
ABSTRACT...................................................................... ..........................................................v i i i
INTRODUCTION.......................................................................................................................
1
REVIEW OF LITERATURE.....................................................................................................
3
MATERIALS AND METHODS ................................................................................................
20
Source o f M a t e r i a l ......................................................................................
Measurements of the Raw R o o t s .........................................................................
Measurements o f the Baked Roots .....................................................................
20
21
25
RESULTS AND DISCUSSION................................................................................................
28
In h e r i t a n c e
Inheritance
In h e r i t a n c e
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
Inheritance
of
of
of
of
of
of
of
of
of
of
of
of
of
of
of
Shape...............................................................................................
Smoothness ..................................................................................
Cortex Thickness of Sweet Potato Roots ..................
Dry M a t t e r ..........................
Carotene .......................................................................................
Skin C o l o r ...................................... .........................................
Characters C o n t r i b u t in g to Baking Q u a l i t y . . . .
Color I n t e n s i t y .........................................................................
Color U n i f o r m i t y .....................................................................
M ois tness......................................................................................
Fl av or ...........................................................................................
Sweetness......................................................................................
Firmness ......................................................................................
F i b e r ................................................................................................
Baking Index ..............................................................................
33
41
46
57
57
64
70
70
70
79
84
93
93
102
112
SUMMARY AND CONCLUSIONS.............................................
115
BIBLIOGRAPHY....................................................................
120
AUTOBIOGRAPHY ...................................................................................................................
129
LIST OF TABLES
TABLE
1.
2.
Page
A D e s c r i p ti o n o f the Characters o f the Raw Roots o f 14
Sweet Potato Breeding Parents ...........................................................
29
A D e s c r i p ti o n o f the Characters o f the Baked Roots of 14
Sweet Potato Breeding Parents .......................
30
3.
The E f f e c t o f Parentage on the A b i l i t y o f Seedlings in
Each Progeny to Produce Roots t h a t Stor e W e l l .............................32
4.
Comparative Data of Seedlings when Parents used as a
Male or Female......................
34
5.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seed­
lin gs o f Each Progeny i n t o D i f f e r e n t Length:Width R a tio
C l a s s e s ................................................................................................................... 35
6.
Percentage o f Sweet Potato Seedlings o f Each Progeny in
D i f f e r e n t Length:Width R a t i o Classes. . .....................................
37
7.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
o f Each Progeny in to D i f f e r e n t Classes Based on Smoothness
o f the Root S u r f a c e ........................................................................................42
8.
Percentage of Sweet Potato Seedlings o f
Each Progeny in
the D i f f e r e n t Classes Based on the Smoothness of the Root
S u r f a c e ................................................................................................................... 44
9.
Frequency D i s t r i b u t i o n o f Sweet Potato Seedlings o f Each
Progeny i n to D i f f e r e n t Classes Based on Thickness o f the
Cortex o f the Roots
.......................................................................... 47
10.
Percentage' o f Sweet Potato Seedlings o f
Each Progeny in
D i f f e r e n t Classes Based on Thickness o f Cortex of the
Roots.
........................................................................................................49
11.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
o f Each Progeny i n to D i f f e r e n t Classes Based on Dry M a t t e r
Content ..............................................
. . . . .
53
12.
Percentage o f Sweet Potato Seedlings o f Each Progeny in
D i f f e r e n t Classes Based on Dry M a t t e r Content . . . . . .
iv
55
TABLE
Page
13.
D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings of Each
Progeny i n t o Classes Based on Carotene Content o f the
Roots.................................................................................................................................58
14.
Percentage o f Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Classes Based on Carotne Content of the Roots.
. .
60
15.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
o f Each Progeny into D i f f e r e n t Skin Color Classes .............................65
16.
Percentage o f Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Skin Color Classes .....................................................................
67
17.
Frequency D i s t r i b u t i o n of Number of Sweet Potato Seedlings
in Each Progeny into D i f f e r e n t Classes Based on Color
I n t e n s i t y o f the Baked R o o t s ...........................................................................71
18.
Percentage o f Sweet Potato Seedlings o f Each Progeny in
D i f f e r e n t Classes Based on Color I n t e n s i t y o f Baked Roots.
.
73
19.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
in Each Progeny in to D i f f e r e n t Classes Based on Uniformi ty
o f Coior o f the Baked Roots............................................................................... 75
20.
Percentage o f Sweet Potato Seedlings o f Each Progeny in
D i f f e r e n t Classes Based on U n if o r m it y o f Color of the
Baked Roots....................................................................................................................77
21.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
o f Each Progeny into D i f f e r e n t Classes Based on Moistness
o f the Baked R o o t s ................................................................................................. 80
22.
Percentage o f Sweet Potato
D i f f e r e n t Classes Based on
Seedlings o f Each Progeny in
Moistness of the Baked Roots.
. .
82
23.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
o f Each Progeny in to Classes Based on F l a v o r of the Baked
Roots................................................................................................................................. 85
24.
Percentage o f Sweet Potato
D i f f e r e n t Classes Based on
Seedlings o f Each Progeny in
F l a v o r o f the Baked Roots . . . .
87
25-
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
o f Each Progeny in to D i f f e r e n t Classes Based on Sweetness
o f the Baked R o o t s ................................................................................................. 89
26.
Percentage o f Sweet Potato
D i f f e r e n t Classes Based on
27.
Seedlings o f Each Progeny in
Sweetness of the Baked Roots.
. .
91
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
of Each Progeny in to D i f f e r e n t Classes Based on Firmness
o f the Baked Roots .
........................................................................................ 94
v
Page
TABLE
28.
Percentage o f Sweet Potato Seedlings of Each Progeny in
The D i f f e r e n t Classes Based on Firmness of the Baked Roots. '. 96
29.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
of Each Progeny i n t o D i f f e r e n t Classes Based on Percentage
F i b e r in the Baked Roots......................................................................................98
30.
Percentage o f Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Classes Based on Percentage F i b e r in the Baked
R o o t s .............................................................................................................................100
31.
Frequency D i s t r i b u t i o n of Number of Sweet Potato Seedlings
o f Each Progeny i n to D i f f e r e n t Classes Based on F i b e r S i z e .
.106
Percentage of Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Classes Based on F i b e r S i z e ........................................
.108
32.
.
33.
Frequency D i s t r i b u t i o n o f Number o f Sweet Potato Seedlings
of Each Progeny i n t o D i f f e r e n t Classes Based on the Baking
I ndex
................................................................................................................... . 1 1 0
3^.
Percentage of Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Classes Based on the Baking I n d e x ...................................... I l l
35.
C o r r e l a t i o n C o e f f i c i e n t s Between Some V a r i a b l e s in the F]
Progenies of the 21 Parental Combinations............................................. 113
vi
LIST OF PLATES
PLATE
1.
Page
The Sweet Potato Skin Color Sc ale, Prepared by the
Un ite d States Department o f A g r i c u l t u r e in Coopera­
t i o n w i t h the Sweet Potato C o lla bo r at or s Conference,
Represents from L e f t to Ri gh t; Purple, Rose, Copper,
Tan and Cream C o lo r s ....................................
22
2.
The Scale Used f o r Smoothness of Root Surface, R a t ­
ings were, by Columns, L e f t to Ri ght ; 1, 2, 3, 4 and
5 R e s p e c t i v e l y ......................................................................................................24
3.
The F i b e r Diameter Scale as I l l u s t r a t e d is Represent­
ed by Values:
Top Rows; ( L e f t to R i gh t) l=Very Coarse,
2=Coarse; Bottom Row; 3=Medium, 4= Fin e, and 5=Very Fine
( 1 . 5 Time Actual S i z e ) ...........................................................
*
26
4.
V a r i a t i o n s in Shape Observed in the F) Progeny of the
Cross L3-77 x L3-80:
Lower Row Represents De si ra bl e
Length........................................................................................................................40
5-
Two Examples of Severe Cracking of the Roots Occurring
Appar ent ly Ea rly in the Growing Season...............................................45
6.
V a r i a t i o n in the Thickness and Color o f the Cortex in
Roots o f the Progeny of the Cross L3-93 x L l - 8 0 ...................
52
7.
V a r i a t i o n in the I n t e r n a l Color o f the Roots in the
Fj Progeny o f the Cross L3-93 x L l - 8 0 ...............................................62
8.
Skin Color V a r i a t i o n o f Roots of D i f f e r e n t Seedlings
in the F] Progeny o f the Cross L3-77 x L 3 - 8 0 ................................. 69
9.
F i b e r Content in 25 Grams o f Baked Root Tissue in each
o f two Seedlings o f L3-77 x Kandee Progeny.
Seedling
w it h Lowest F i b e r Content ( L e f t ) and Seedling wit h
Highest Fi ber Content ( R ig ht ) ............................................................
103
F i b e r Content in 25 Grams o f Baked Root Tissue in each
o f two Seedlings o f 0K51 x L 131 - Seedling w it h Lowest
F i b e r Content ( L e f t ) and Seedling w i t h Highest F i b e r
Content ( R i g h t ) ..................................................
105
10.
vi i
ABSTRACT
The Fj progenies of 21 d i f f e r e n t combinations
in vo lv in g 14 sweet
po ta to breeding parents were grown a t Chase, Louisiana in 1964.
roots of each seed ling were harvested September 16,
to M is s is s ip p i
State U n i v e r s i t y ,
1964, t ra nsp or te d
cured, stored and e va lu a te d .
roots were ev a lu a te d f o r shape, smoothness, carotene
c o n t e n t ) , c o r t e x t hic kne ss , dry m a t t e r ,
were baked and ev al ua ted f o r fir m nes s,
The
(total
and skiri c o l o r .
The raw
pigment
The roots
c o l o r , moistness, sweetness,
f l a v o r and f i b e r .
Shape as d e t e r m i n e d by the
be a h e r i t a b l e c h a r a c t e r .
genes c o n t r o l l i n g
(L:W) r a t i o appeared t o
Transgressive segregation occurred.
t h i s c h a r a c t e r appeared a d d i t i v e
absence o f dominance.
tro llin g
le n g th iw id th
The
in e f f e c t w i t h the
There was no i n t e r a c t i o n between genes con­
shape o f th e r o o t s and number o f r o o t s per p l a n t .
The progenies were ev a lu a te d f o r surface smoothness as an e s t i ­
mate of freedom from v e in in g and cr a c k in g .
Ve ining and possible
causes of c r ac ki ng were discussed.
The genes c o n t r o l l i n g c o r t e x thickness segregated
tr a n s g r e s s iv e manner in each progeny.
in a t y p i c a l l y
This ch a ra c t e r appeared to be
c o n t r o l l e d by a r e l a t i v e l y few genes w it h simple a d d i t i v e e f f e c t s .
The genes f o r dry m a t t e r content segregated t r a n s g r e s s i v e l y .
There were in each progeny s e e d l i n g s h i g h e r t h a n th e h i g h e s t p a r e n t
and lo we r t h a n th e
lowe st p a r e n t .
G e n e r a l l y t h e progeny mean was
lo we r than t h e mean o f th e two p a r e n t s .
vi i I
I t was conc lud ed t h a t d r y
ma tter was a q u a n t i t a t i v e ch a ra c t e r c o n t r o l l e d by several
ing dominance but a d d i t i v e
genes la ck ­
in e f f e c t .
In most progenies the mean f o r carotene c l o s e l y approached the
mean of the two pa re n ts .
Carotene content was a q u a n t i t a t i v e charac­
t e r and segregated t r a n s g r e s s i v e 1y.
additive
The genes, probably 6, were
in e f f e c t w it h dominance absent and i n h i b i t o r or e p i s t a t i c
e f f e c t s were suggested.
C o r r e l a t i o n s of carotene con ten t of roots
w it h c e r t a i n o th er ch ara ct ers were shown and discussed.
In a l l
greater
progenies the female parent appeared to have e xe rte d a
i n flu en c e on skin co lo r than did the male p a r e n t .
c o n t r o l l i n g t h i s ch a ra c t e r segregated t r a n s g r e s s i v e l y .
were involved and appeared a d d i t i v e
in e f f e c t .
The genes
Several
genes
The presence of an
i n h i b i t o r , or one or more complementary genes was i n d i c a t e d .
Color
intensity
in the baked root was shown to be c l o s e l y c o r r e ­
lated to the carotene content as determined chromatographica1l y .
U n if o r m it y o f c o l o r appeared to be a g e n et ic t r a i t c o n t r o l l e d by a
small number o f genes w it h a t
least p a r t ia l
dominance.
Moistness of the baked roots reacted as a q u a n t i t a t i v e c ha ra ct er
c o n t r o l l e d by several
genes segregating t r a n s g r e s s i v e l y .
Dominance
was not e v i d e n t ; an a d d i t i v e e f f e c t was suggested.
The data
ind ic at ed t h a t good or su pe rio r f l a v o r and sweetness
were recessive c h a r a c t e r s .
Very few i n d i v i d u a l s
in any progeny pos­
sessed a f l a v o r su pe rio r to t h a t o f the more d e s i r a b l e parent but many
i n d iv id u a ls were i n f e r i o r to the poorer p a r e n t.
A close p o s i t i v e
c o r r e l a t i o n was found between f l a v o r and sweetness.
A pos sible asso­
c i a t i o n w it h one or more enzyme systems as conversion f a c t o r s during
baking was suggested.
Firmness appeared to be a q u a n t i t a t i v e c h a r a c t e r c o n t r o l l e d by
several
genes segregating t r a n s g r e s s i v e l y .
The high p o s i t i v e
correla­
tions between firmness and carotene and /or moi.stness and the negative
c o r r e l a t i o n between firmness and dry m a t te r ind ic at ed t h a t
may e x i s t .
A close c o r r e l a t i o n was shown between t o t a l
and siz e of the i n d i v i d u a l
involved.
A small group,
linkages
f i b e r content
f i b e r s but two d i s t i n c t sets o f f a c t o r s were
probably not more than 2 p a i r s , of genes w ith
simple dominance c o n t r o l l e d s i z e but t o t a l f i b e r content was c o n t r o l l e d
by several
genes, geometric in e f f e c t and link ed w ith those f o r s i z e .
The baking index was obtained as the average score o f the q u a l i t y
components.
This study has shown t h a t baking q u a l i t y
t r a i t c o n t r o l l e d by a complex of ge n eti c ch a ra c t e r s .
x
is a h e r i t a b l e
INTRODUCTION
The pop ulation o f the United States and the world has grown q u i t e
r a p i d l y in the past 50 yea rs .
unchecked,
the United Stat es w i l l
bout 60 years
rate.
I f the pop ulation explosion continues
(9).
double the present pop ulation
in a-
The world pop ulatio n is growing a t an even f a s t e r
In several areas of the world major food shortages are causing
severe famines and m a l n u t r i t i o n w ith
the people involved.
i t s accompanying i l l
e f f e c t s on
In the not too d i s t a n t f u t u r e the United States
could be faced w it h the problem of f ee di ng a hungry n a t i o n .
The sweet p ot at o,
(Ipomoea ba t a t a s ) a n a t i v e o f T r o p i c a l America
and the West I n d ie s , may become i n c r e a s i n g l y more important as a source
of food.
drat es
I t has been used f o r many years as a r i c h source of carbohy­
in t r o p i c a l
and s u b - t r o p i c a l
co u nt ri es o f the world (25,
This crop is w el l adapted to the c l i m a t i c con di tio ns e x i s t i n g
103).
in large
areas of the southern Un ite d Stat es and c e r t a i n e a r l i e r producing
v a r i e t i e s are grown as f a r north as southwestern Michigan and along
the A t l a n t i c Coast i n to New Jersey and neighboring areas.
It
is the
most important veg etable crop o f the southern United St at es both in
acreage and monetary value.
The economic p r o s p e r i t y and abundant food supply of the United
Stat es have enabled the American consumers to place more emphasis on
the demand f o r a highe r q u a l i t y food product.
in 1937 a t
M ille r's
(70)
success
inducing the sweet potat o to bloom and set seed in the
United Stat es opened the door to a vast breeding program aimed at
2
improving the y i e l d and q u a l i t y o f t h i s crop.
Carotenoid pigments,
p a r t ic u la r ly beta-carotene,
gives the y e l l o w
c o l o r to the f l e s h of the sweet p o t a t o root and is found in va r y in g
co n ce n t r a ti o n s
imp ortant
in most sweet p o t a t o v a r i e t i e s .
B e ta -c a ro te n e
is ver y
in the d i e t o f man as a precursor o f v i ta m i n A which is so
necessary f o r good h e a l t h .
The success of the breeding program in im­
proving the q u a l i t y o f sweet potatoes
is a t t e s t e d by newer v a r i e t i e s
w i t h much hi gh er ca ro te ne content than the o l d e r ones ( 7 3 ) .
Q uality
factors.
ter,
is c o n t r o l l e d by a complex of g e n e t i c
Some o f these ch a ra c t e r s such as carotene c o n t e n t , dry mat­
fib e r,
Others,
in the sweet potat o
firmness and root shape may be measured by o b j e c t i v e means.
such as smoothness, u n i f o r m i t y , moistness, f l a v o r and sweet­
ness must be ev a lu a te d s u b j e c t i v e l y and is
strong personal
infl ue nc ed
pr ef e r e n c e s .
This study was i n i t i a t e d t o determine the mode o f
root shape, f i b e r c o n t e n t ,
pigments
in some cases,
(ca ro te ne )
skin c o l o r ,
dry m a t t e r ,
i n h e r i t a n c e of
total
ca r o t e n o id
and o t h e r f a c t o r s c o n t r i b u t i n g t o a high y i e l d
and good baking q u a l i t y
in the sweet po ta to .
by
REVIEW OF LITERATURE
E a r l y Hi s t o r y
The sweet potat o is n a t i v e of the New World having o r i g i n a t e d
the t r o p i c a l
103).
times
and s u b - t r o p i c a l
areas of Central
According to Cooley ( 2 5 ) ,
and South America (25,
i t was used f o r food in p r e h i s t o r i c
in the t r o p i c a l Americas and some of the P a c i f i c
is evidence t h a t
in
Is la nd s.
There
i t was introduced in to New Zealand p r i o r to the Spanish
e x p l o r a t i o n s but i t was not known to the a n c ie n t c i v i l i z a t i o n s of As ia ,
A f r i c a and Europe.
Columbus found the n at iv es o f Cuba using the sweet
potat o f o r food and i t
is g e n e r a l l y b e l i e v e d he c a r r i e d
i t to Europe
probably on his f o u r t h voyage.
The sweet p o t a t o ,
Ipomoea b a t a t a s
the C o n v o lv u la c e a e f a m i l y t h a t
f o o d f o r man (51,
103).
(L.)
LAM.,
is o f m a jo r im p o r t a n c e as a source o f
K i n g and Bamford (61)
i n d i c a t e d t h a t th e sweet p o t a t o
in t h e i r s tu d ie s
in
1937
i s an e x t r e m e l y h e t e r o z y g o u s f i e x a p l o i d
w i t h a s o m a t ic chromosome number o f 90.
T i n g and Kehr (10**)
suggested t h a t th e sweet p o t a t o was an a l l o p l o i d
o f m u ltiv a le n ts ,
i s th e o n l y member o f
in o r i g i n .
in 1953
The absence
t h e presence o f secondary a s s o c i a t i o n s and t h e h i g h
number o f chromosomes in th e sp e c i e s were used as e v i d e n c e
a t t h e i r theory o f a l l o p l o i d o r i g i n .
in a r r i v i n g
They b e l i e v e d the sweet p o t a t o
a ro se as a h y b r i d between two unknown s p e c i e s , one a t e t r a p l o i d and th e
o t h e r a d i p l o i d and the n a t u r a l
d o u b l i n g o f t h e chromosomes o f t h i s
b r i d gave r i s e t o t h e modern sweet p o t a t o ,
able.
but t h i s
is s t i l l
A number o f w o r k e r s have r e p o r t e d on a t t e m p t s a t
hy­
question­
in te rs p e c ific
4
hybridization
in the genus but no one has been succesful as y e t .
The sweet po ta to has been an important food crop f o r many years.
It
is c r e d i t e d w ith saving the Japanese from famine on several occasions
and s i m i l a r commendations are bestowed upon i t by a number of ot her
countries.
According to Thompson (103) the sweet po ta to is a standard
a r t i c l e of food in the southern United S t a t e s .
place
He ranks i t
in importance as veg etable crop in the United S t a t e s .
important food crop in a l l
sub-tropical
in fo u r th
It
is an
c ou nt r ie s of the world having a t r o p i c a l or
c l im a t e and production extends w el l
i n to the temperate
area .
To ta l
Carotenoid Pigment
E a rl y workers
(13,
(Carotene)
Inheri tance
16, 25, 26, 31, ^8,
50, 60, 68, 72) w i t h the
crop re por te d on the wide range o f d i f f e r e n c e s among v a r i e t i e s
c o l o r of the f l e s h .
w ithin a v a rie ty ,
Some have reported on the occurrence of mutations,
f o r f l e s h c o l o r and t h i s has been used to advantage in
v a r i e t y development programs.
The p r i n c i p a l
pigment responsible f o r
f l e s h c o l o r has been i d e n t i f i e d as b e t a - c a r o t e n e
(32)
i d e n t i f i e d several o t h e r pigments
(32).
E z e l l and Wilcox
in sweet potatoes;
accounted f o r not more than 10 per cent of the t o t a l
Furthermore,
in the
pigments present.
they reported the r a t i o of carotene to t o t a l
came wider as the i n t e n s i t y of the ye l l o w c o l o r
however, they
pigments be­
increased, but i t va r i e d
among v a r i e t i e s .
Numerous environmental e f f e c t s upon the carotene content of sweet
po t at o roots have been r e po r te d.
Covington (26) found t h a t the caro­
tene content was infl uen ce d by tem pera ture , f e r t i l i z e r s ,
s o i l m oistu re,
storage co n d it io n s and h e i g h t of rid ge on which the p l a n t s were grown.
Covington (26) al s o reported a s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n between
height of ridge and carotene c o n te n t.
The data of Edmond, e_t aj_ (31)
i n d i c a t e a tendency in t h i s d i r e c t i o n .
Burton ( 1 8 ) ,
studied the in ­
flue nce o f v a r i e t i e s and storage p r a c t i c e s on the q u a l i t y of sweet
potato c h i p s .
t re a t m e n t.
He noted an increased carotene content from a preheat
A number o f ot her workers
(40, 41, 43, 44, 5 5 - 6 0 , 72, 92,
95) have i n di c at ed t h a t the carotene content
however,
i t should be noted t h a t these
son to the t o t a l
increased during storage;
increases were small
in compari­
amount of pigment pr ese nt.
Several workers have discussed at various times and under d i f f e r e n t
environmental c on di tio ns an e f f e c t o f p l a n t i n g date on the carotene con­
tent.
As might be expected in a p l a n t as heterozyous as the sweet pota­
to and as markedly influenced by environment as I t seems t o be, much of
the data on the e f f e c t of p l a n t i n g date is in d i r e c t c o n f l i c t .
(33)
Fong
in 1951 re por te d t h a t e a r l i e r p l a n t in g s were higher in carotene
than l a t e r ones.
in t h a t
This was a l s o suggested by the work of Gaafar
(34)
longer l i g h t exposure increased the carotene and sugar content
of roots.
Kimbrough, et_ aj_ (60) were unable to f i n d any c o r r e l a t i o n s
between p l a n t i n g date and c o l o r .
Anderson and his associates
( 2 , 3» 4,
5) made number o f r a t h e r d e t a i l e d stu die s of the e f f e c t s of p l a n t i n g
date on the r o o t s .
In one season (1941)
they noted a tendency toward
an e a r l y p l a n t i n g - high carotene a s s o c i a t i o n
Hines
(50) suggested t h a t the area o f production in flu enc ed marked­
ly the exp ression of a number o f ch a ra ct er s
flesh.
(6).
Reddy (85)
flesh color.
i nc lu din g the c o l o r o f the
report ed a s i g n i f i c a n t e f f e c t o f production area on
Jenkins and his co-workers observed a marked d i f f e r e n c e
in
the c o l o r o f canned roots o f a v a r i e t y when grown in d i f f e r e n t areas of
Mississippi.
Massey e t aj_ ( 6 7 ) reported s i m i l a r r e s u l t s
in raw roots
6
of sweet potatoes grown in d i f f e r e n t
l o c a t io n s
in V i r g i n i a .
This
is
f u r t h e r supported by the work o f Hammett (41) w i t h canned sweet pota­
toes in which he found d i f f e r e n c e s very s i m i l a r t o those of Jenkins.
In a d d i t i o n ,
he re po rt ed a h i g h l y s i g n i f i c a n t
i e t i e s and l o c a t io n s f o r
ments.
i n t e r a c t i o n between v a r ­
f l e s h c o l o r and most o t h e r q u a l i t y
Stevenson and Akeley
(101) working w it h potatoes and Janes
working w i t h
cabbage and beans found s i m i l a r responses t h a t
a t tr ib u t e to
no v a r i a b l e o t h e r than pr odu ction
There is e vi de n ce , although much o f
it
fe rtiliz e rs
on the c o l o r o f the roots as e a r l y as 1941
failed
Samuels and Landrau
that
Covington recorded an e f f e c t of
re po rt ed s i m i l a r r e s u l t s
in his e f f o r t s
they could
is c o n t r a d i c t o r y ,
influence fle s h color.
Rico as did Janes (52)
(52)
location.
fe rtiliz e rs
e t aj_ (31)
measure­
(26).
Edmond
in t h e i r work w it h the U n it
in hi s work w i t h o t h e r v a r i e t i e s .
I Porto
Reddy (85)
to associate fle s h color w ith f e r t i l i z e r s .
(89)
stated that " f e r t i l i z e r s
increased carotene
content o f the roots only when they increased the y i e l d s i g n i f i c a n t l y
but t h a t
in c r e a s i n g the s o i l
ment c o n c e n t r a t i o n " .
pH above 4 . 5 did
increase the y e l l o w pi g­
The in fl u e n c e o f f e r t i l i z e r s ,
pH and s o i l moisture
on the c o l o r and processing q u a l i t y o f a wide v a r i e t y of h o r t i c u l t u r a l
crops has been re ported from time to t im e.
I t was recognized soon a f t e r the breeding program was begun th a t
c o l o r o f the f l e s h was a h e r i t a b l e t r a i t .
M i l l e r and Covington
(72)
s t a t e d as e a r l y as 1942 t h a t ------ " a l th o u g h the carotene content may be
changed by c u l t u r a l
method o f
tre atme nts and environmental
in cr e a s i n g the carotene
s t ud ie s on the
factors
is h y b r i d i z a t i o n " .
the best
One o f the e a r l y
i n h e r i t a n c e o f carotene was conducted by Hernandez ( 4 8 ) .
He found the sweet po t at o t o be very heterozygous f o r t h i s and o t h e r
7
c ha rac te rs which included vine
roo ts ,
length and c o l o r ,
l e a f shape and m a t u r i t y dat e.
skin c o l o r o f the
M i k e l l ejt aj_ (68) suggested th at
both skin and f l e s h co lo r were c o n t r o l l e d by m u l t i p l e genes plus the
possible presence of complementary f a c t o r s .
c o l o r was " i n h e r i t e d
dihybrid
in a complex manner and segregated as a dependent
in e i t h e r a 9 :7 or 13:3 r a t i o " ;
o b t a i n in g a good f i t
Poole (84) proposed f l e s h
fo r this r a t io .
however, he had d i f f i c u l t y
in
He concluded t her e was both a
dominant and recessive orange f l e s h and t h a t f l e s h and skin c o l o r were
l in k e d .
Hernandez ( 4 9 ) , working w it h d i f f e r e n t populations came to the
conclusion th a t white f l e s h
is incompletely dominant over orange f l e s h .
He e x p la in ed the r a t i o he obtained as being due to the e p i s t a t i c act ion
of two or more w hi te genes over genes f o r orange f l e s h or the possible
presence o f an i n h i b i t o r gene.
He proposed t h a t s i x genes a c t i n g
an a d d i t i v e manner c o n t r o l l e d f l e s h c o l o r .
He also reported a h ig hl y
s i g n i f i c a n t c o r r e l a t i o n between skin and f l e s h c o l o r .
found f l e s h c o l o r was i n h e r i t e d q u a n t a t i v e l y
and was c o n t r o l l e d by several
in
Constantin
(24)
in a t r a n s g r e s s iv e manner
genes e i t h e r a d d i t i v e or geometric in
ac t i o n .
Skin Color
A number of the e a r l y works recorded v a r i e t a l
c o l o r o f the sweet potato roots
(5,
differences
16, 31, 41, 48, 51, 6 8 ) .
in skin
These
d i f f e r e n c e s have ranged from a l i g h t cream or wh ite to a very dark purr
pie.
D e s c r i p t i v e terms used in d e s c r ib i n g the skin c o l o r v a r i e s wide ly
among i n d iv id u a l workers and from region to regi on.
These d i f f e r e n c e s
among workers and loc at io ns make i t very d i f f i c u l t to be sure t h a t
differences
in skin co lo r ar e due to l o c a t i o n e f f e c t s ;
however, there
8
are some repo rt s
in which one worker had made observations o f samples
o f a given v a r i e t y from several production ar eas.
Luh (66) working
w i t h pear f r u i t s described such l o c a t io n e f f e c t s on the f r u i t c o l o r .
Hines
(50)
in 19^+9 and Hammett (41)
in 1962 described skin c o l o r
d i f f e r e n c e s w i t h i n a given v a r i e t y of sweet potatoes when I t was grown
in d i f f e r e n t
locations.
g r e a t e r than v a r i e t a l
D if fe r e n c e s due to l o c a t io n were f r e q u e n t l y
differences.
Hernandez* study (48)
one o f the f i r s t attempts to e x p l a i n v a r i e t a l
color.
differences
in 1942 was
in skin
Poole (84) found skin c o l o r to be c o n t r o l l e d by two genes t h a t
were linke d w i t h the genes f o r f l e s h c o l o r .
Hernandez (49)
reported
skin c o l o r was a q u a n t i t a t i v e c h a r a c t e r as opposed t o Poole's conclu­
sion t h a t I t was a q u a l i t a t i v e c h a r a c t e r .
Hernandez (49) f u r t h e r pro­
posed the presence o f two complementary genes and po ss ib ly a t h i r d
gene basic f o r c o l o r .
linked.
tive ly
tary
Constantin
He al so concluded t h a t f l e s h and skin co lo r were
(24) s t a t e d , " s k i n c o l o r appears t o be q u a n t i t a ­
i n h e r i t e d w it h several
i n t e r a c t i n g genes, probably complemen­
in a c t i o n . . . . p u r p le skin c o l o r appeared to be p a r t i a l l y dominant
over the o t h e r skin c o l o r s " .
Dry M at te r
H a s s e l b r i n g and Hawkins (43, 44) not ed v a r i e t a l
t h e d r y m a t t e r c o n t e n t o f sweet p o t a t o e s .
S i s t r u n k and c o - w o r k e r s
(75,
76) have r e p o r t e d v a r i e t a l
p u b l i s h e d d a t a showing a wide range o f v a r i a t i o n
12,
14,
and s e e d l i n g s .
15, 20, 52, 53, 57, 82, 8 5 , 96,
in
Boswell ejt a_[ (16) and
in d r y m a t t e r o f sweet p o t a t o e s and o t h e r c r o p s .
sweet p o t a t o v a r i e t i e s
differences
differences
M i l l e r , _e_t _aj_ (73)
in d r y m a t t e r o f
Numerous o t h e r w o rk er s
108,
(1,
111) have a l s o shown
11,
9
varietal
differences
in dry m at te r content o f sweet potatoes and a
number o f ot her crops.
These crops include such pl ant s as beans ( 5 2 ) ,
cabbage ( 5 2 ) , cantaloupe (2 7 , 11*0, c a r r o t s
(7),
pear (63,
3 10) and strawberry
mong these crops and sweet potatoes
on v a r i e t a l
variation
(111).
( 2 0 ) , potat o ( 1 1 ) ,
radish
The g r e a t e s t s i m i l a r i t y a-
is the consistency of the reports
in dry mat ter co n te n t.
However, f a c t o r s other
than v a r i e t y have been shown t o in flu en ce the dry m at ter con ten t.
Robbins e_t a_l_ ( 87) concluded in 1929 t h a t f e r t i l i z e r s
m at ter
in sweet potatoes.
Reddy (8 5 ) reported in 1952 t h a t he was un­
able to f i n d such an infl uen ce in his work;
w i t h sweet potatoes
tween f e r t i l i z e r s
workers
tatoes.
infl uen ce dry
however, oth er workers
(5 , 21, 3 1 , 79, 80) have re ported c o r r e l a t i o n s be­
and dry m a t te r con ten t.
Jasmin ejt aj_ (53) and other
(11, 82, 88) have found an in flu en ce due t o f e r t i l i z e r s
Janes (52)
reported a f e r t i l i z e r e f f e c t
in po­
in cabbage and beans
but he found a much g r e a t e r e f f e c t due to the area o f production.
Boswell and his co-workers
area o f production,
(16) found s i g n i f i c a n t d i f f e r e n c e s due to
season and v a r i e t i e s w it h sweet pot ato es.
r e s u l t s were reported by Hammett in M is s i s s i p p i
Virg in ia
(67) .
(41) and Massey in
S i s t r u n k (96) working w it h beans, found d i f f e r e n c e s
dry m a t t e r a f f e c t e d by mulches,
Peterson
Sim ilar
i r r i g a t i o n and v a r i e t i e s .
in
C a rl t o n and
(20) were able to increase the dry m at ter content of ca r r o t s
by f o l l o w i n g a program of s e l e c t i o n and inbreeding.
Peterson ( 8 2 ) ,
P l a i s t e d and
r e p o r t i n g on t h e i r work w i t h potatoes concluded, a f t e r
two cycles of r e c u r r e n t s e l e c t i o n ,
t h a t the program was e f f e c t i v e as
a means of increas ing the s p e c i f i c g r a v i t y .
Stevenson and Akeley (101)
On the o th er hand,
reported t h a t environmental
f r e q u e n t l y g r e a t e r than v a r i e t a l
responses.
responses were
Hernandez (49) found dry
10
m a t te r in sweet potatoes was i n h e r i t e d
in a t ra ns gr es si v e manner and
t h a t a h i g h l y s i g n i f i c a n t neg ative c o r r e l a t i o n e x i s t e d between dry
m a t te r and caro ten oid pi gm entation.
The r e s u l t s obtained by Constantin
(24) c l o s e l y supported those of Hernandez.
Shape and Smoothness
Shape in the sweet p o t a t o ,
as determined by the le ngt h: wid th
(L:W) r a t i o and smoothness or freedom from v e i n s ,
o r o th er growth defects such as large l a t e r a l
rid ges , cracking
feed roots probably in ­
f lu e n ce the consumer-purchaser o f f re sh sweet potatoes more than any
other fa c t o r .
In general sweet po ta to es, w ith a L:W r a t i o of about 2,
f r e e of smoothness defec ts seem t o be the type p r e f e r r e d f o r most
f re s h markets.
The i n flu en c e o f c u l t u r a l
and environmental f a c t o r s
on the shape of sweet po t at o roots was studied by a number o f e a r l y
workers.
Robbins et_ aj_ (®7) reported t h a t potassium was necessary
f o r p r o t e i n synthesis and development of storage t is s u e and th e r e f o r e
is e s s e n t i a l f o r production of roots w i t h low L:W r a t i o s .
(116) associated shape w i t h both ni tr o g e n and potassium.
Zimmerly
M i l l e r and
Kimbrough (69) and Edmond (30) found a very marked influence of date
o f p l a n t i n g on shape o f the r o o t s .
Edmond and co-workers
(30, 31)
noted t h a t p l a n t i n g date and he ig ht of ridge influenced shape.
Anderson (2, 3) report ed th a t n itr og en and potassium had no e f f e c t on
the shape o f Triumph sweet potatoes but he did in d ic a t e t h a t s o i l
may have some e f f e c t .
(50).
type
This was supported in p a r t by the work of Hines
Anderson and his asso cia tes
spacing and rid ge he ig ht
(4, 5> 6) found p l a n t i n g d at e,
influenced the shape o f the ro ot s.
s t a t e d t h a t the l a t e r the p l a n t i n g d a t e ,
They
the w ide r was the L:W r a t i o .
11
Angel 1 and Hi 1 I y e r
dish ro ot s.
(7) studied the photoperiod response of r a ­
They found a very marked v a r i e t a l
response in diameter,
weight and number of days requi re d to reach marketable s i z e .
(22) t h e o r i z e d t h a t some p l a n t growth substance t h a t
Chapman
is produced under
sh o rt day con ditions was necessary f o r tuber for ma tion in potatoes.
Several workers
f e c t s o f temperature
In general
(22, 81, 88,
on tuber
109,
115) have reported on the e f ­
f or m a tio n, y i e l d , and shape o f potatoes.
they found t h a t higher temperatures had adverse e f f e c t s on
both shape and y i e l d .
on pot at oes .
Went (109) al so discussed temperature e f f e c t s
He suggested some p l a n t growth substance as being re ­
sponsible f o r the e f f e c t s .
Audus (10) and Leopold (6U) have e l a b o r a t ­
ed on t h i s po in t as i t was influenced by both temperature and dayle ng th .
Jenkins (5*0 reported t h a t long days and r e l a t i v e l y high
temperatures were necessary f o r bulb fo rmation in s h a l l o t s .
Chipman
(23) found t h a t e a r l i e r harvested c a r r o t s had b e t t e r shape than those
harvested l a t e r
in the season.
Yamaguchi ejt aj_ (115) working w it h po ta to es, found the s o i l
temperature had a pronounced e f f e c t on smoothness o f the tub ers.
Those grown a t *+5- 50° F. were very smooth w h il e
tubers grown at BO­
SS0 F. were extremely rough and d i s t o r t e d .
(88) working at
s l i g h t l y d i f f e r e n t soil
Ruf
temperatures reported very s i m i l a r r e s u l t s .
Nusbaum (78) s ta te d t h a t boron d e f i c i e n c i e s caused rough, misshapen
and cracked roots
workers
in the Porto Rico v a r i e t y .
Paterson and his co­
(79, 80) report ed t h a t growing sweet potatoes 2 years in
succession on the same land r e s u l t e d in severe y i e l d reductions due
t o the presence o f rough, s e v er ly cracked and misshapen r oo ts .
and M i l l e r
(97) proposed t h a t a " q u a n t i t a t i v e
Skoog
i n t e r a c t i o n among growth
12
substances is the means f o r r e g u l a t i n g a l l
types of growth.
Morpho­
gen etic e f f e c t s e x i s t but they may be a l t e r e d by the s u b s t i t u t i o n of
one or more growth substances".
Cortex
Hayward (46) described the co r t e x as the l a y e r o f parenchymatous
cells
located between the cambium and periderm.
i d e n t i f i e d the co r t e x as the t is s u e
the endodermis and the epide rm is .
several t o many c e l l s .
that
in pot atoes,
(s)
Smith e t aj_ (99)
l yi n g between, and in cl u d in g ,
The co r t e x v a r i e s
Yamaguchi and his co-workers
the co r t e x was t h i c k e s t
the highest temperature.
in thickness from
(115) reported
in those tubers grown at
On the ot her hand, they found the i n d iv id u a l
c e l l s o f the co rt ex were s m a l le r ,
thicker-w alled
in tubers grown a t
the lowest temperature in a s e r i e s o f t e s t s where the soi l
ranged from 4 5 - 5 0 ° F.
temperature
to 8 0 - 8 5 ° F.
Q.ual ?tv
For sensory e v a l u a t i o n of food products Sather and Ca lv in
suggested t h a t
(90)
in mi I d - f l a v o r e d products up to 20 samples may be in­
cluded in one t e s t period w it h o u t
of the t e s t panel.
impairing the e f f i c i e n c y or accuracy
Dawson (28, 29) al so favored a t e s t of t h i s type
which he termed a " M u lt ip le - S a m p le " comparison t e s t and he l i s t e d a
number o f d i s t i n c t advantages o f the method.
l i s t e d are:
additional
Among the advantages he
a) detec ts sm al le r d i f f e r e n c e s between samples; b) gives
information about the d i r e c t i o n and importance o f the
d i f f e r e n c e s ; c)
requ ir es fewer samples and less time; and d)
is more
e f f i c i e n t when panels have not been s p e c i a l l y se le c t e d or t r a i n e d .
Dawson (28, 29) f u r t h e r suggested t h a t "numerical
scoring of
13
samples is a p p l i c a b l e when the d i f f e r e n c e s can be predetermined and
arranged on a nu m er ic al ly
graduated sca le.
method over a simple ranking method
than the ot her
Q uality
although one was no more e f f i c i e n t
in d e t e c t i n g d i f f e r e n c e s ,
ed degrees of d i f f e r e n c e s
in the sweet
but the scoring method i n d i c a t ­
t h a t were not shown by ranking.
po ta to is a complex of f a c t o r s and is depen­
dent upon many c o n t r i b u t i n g c h a r a c t e r s ,
ence of the i n d i v i d u a l .
He p r e f e r r e d the scoring
inc lud ing the personal p r e f e r ­
Although a number of f a c t o r s are known to a f ­
f e c t the q u a l i t y of the sweet p o t a t o ,
the e x t e n t to which the in d iv id u a l
components a f f e c t the q u a l i t y o f the baked roots
is not known.
Morris
and Mann (7*0 st at ed t h a t the Porto Rico was c o n s i s t e n t l y ra ted higher
than oth er v a r i e t i e s
ness showed l i t t l e
chemical a n a l y s i s .
in e a t i n g q u a l i t y by a t a s t e panel: however, sweet­
o r no r e l a t i o n to sugar content as determined by
Constantin
( 2k) found soluble s o l i d s
(sugar content)
were associated w i t h several o t h e r q u a l i t y measurements, however, he
s t a t e d , "The magnitude of the c o r r e l a t i o n c o e f f i c i e n t s ,
although s t a t i s ­
t i c a l l y s i g n i f i c a n t , was too low to be of any p r a c t i c a l
va lu e" .
S c ot t and Matthews
m a t te r ,
(92) found d i s t i n c t v a r i e t a l
differences
in dry
starch and sugar content o f sweet potato roots at the time of
harvest and during the storage p e r i o d .
that total
S i strunk e_t _a_l_ (95)
reported
sugars In f re sh sweet potatoes seemed to have l i t t l e e f f e c t
on the t o t a l
sugars in the cooked roots.
They found no d i f f e r e n c e s
in
the f re sh roots among the v a r i e t i e s t es te d w i t h the exception of Queen
Mary, but Porto Rico converted the highest percentage of reducing
sugars during baking.
Hammett and B a rr e n ti n e
(**0) and Jenkins and
Gieger (57, 58) have a l s o shown marked v a r i e t a l
differences
in sugar
conversion during baking and in each t e s t Porto Rico had the highest
14
conversion ra te .
Numerous workers have in v e s t i g a t e d the
influence of v a r i e t y and
production locations on the q u a l i t y of various f r u i t and vegetable
crops.
Ba rri os £ t a_l_ (11) noted mealiness as one o f the f a c t o r s a f f e c t ­
ing q u a l i t y
in the p o ta to .
and siz e o f the i n d iv id u a l
They found c e l l
size,
total
starch content
sta rc h grains to be c o r r e l a t e d to the m e a l i ­
ness r a t i n g of the potatoes and these c h a r a c t e r i s t i c s were st r o n g l y
fluenced by v a r i e t y and environment.
Jasmin and his co-workers
in ­
(53)
re­
ported s p e c i f i c g r a v i t y and b o i l i n g q u a l i t y o f potat o tubers were ad­
v e r s e ly a f f e c t e d by heavy a p p l i c a t i o n s of f e r t i l i z e r s .
Stevenson and
Akeley (101) st at ed t h a t environmental e f f e c t s were of te n g r e a t e r than
varietal
differences
in determining potato chip q u a l i t y and t h a t a
strong v a r i e t y - e n v i r o n m e n t i n t e r a c t i o n was p r e v a l e n t .
D a v is , Baker and Kasmire
Louisiana,
lou pes .
(27)
in C a l i f o r n i a ,
and Woodward (114)
in
s t u d i e d some o f the q u a l i t y f a c t o r s o f muskmelons and c a n t a ­
They noted a number o f v a r i e t y and e n v i r o n m e n t a l
influences
t h a t were c o r r e l a t e d b u t t h e y were unable t o f i n d a c o n s i s t e n t c o r r e l a ­
t i o n w i t h t h e q u a l i t y o f the f r u i t .
The C a l i f o r n i a
r e p o r t n ot ed wide
v a r i a t i o n s among i n d i v i d u a l melons from a s i n g l e s i t e and between any
two s i t e s .
Hall
They concl uded t h a t t h e p o p u l a t i o n s were v e r y h e t e r o z y g o u s .
( 3 9 ) , w o r k i n g w i t h toma toe s,
found f i r m n e s s t o be a v a r i e t a l
r a c t e r i s t i c not associated w ith rip e n in g .
Pinthus
(83)
ly s ig n if ic a n t v a rie ty diffe re n ce s
in wheat k e r n e l
t e i n c o n t e n t and endosperm c o l o r .
W i l l i a m s ejt aj_ (112)
r i c e q u a l i t y and r e l a t e d
it
size ,
t o th e s t a r c h f r a c t i o n s .
cha­
r ec or de d h i g h ­
ha rd ne ss , p r o ­
investigated
They r e p o r t e d a
v e r y c l o s e c o r r e l a t i o n between th e s t a r c h f r a c t i o n expressed as amylose
o r a m y l o p e c t i n and the g r a i n
le ngth.
Luh and h i s c o - w o r k e r s
(66)
reported t h a t q u a l i t y of canned pears was r e l a t e d to the growing area.
W ile y and Thompson (110) found t h a t v a r i e t y ,
storage con ditio ns and ma­
t u r i t y had a marked infl ue nc e on the q u a l i t y of canned apples.
e t aj_ (111) noted v a r i e t a l
ty.
and seasonal d i f f e r e n c e s
They al s o reported a v a r i e t y - s e a s o n
o f the f r u i t .
cultural
in strawberry q u a l i ­
interaction a ffe ctin g quality
S i s t r u n k and his co-workers
cal and physical
( 96) found th a t both chemi­
p r o p e r t i e s of beans were a f f e c t e d by several
p r a c t i c e s , and Janes (52)
e f f e c t than the v a r i e t y .
Jenkins
Wolford
common
found th a t environment had a g r e a t e r
(59)
reported v a r i e t a l
differences
in
the q u a l i t y c o n s ti t u e n t s of southern peas and a l s o a very pronounced
varietal
difference
in r a t e of change in these c o n s ti t u e n t s f o l l o w i n g
harvest.
A number of workers have i n v e s t i g a t e d the e f f e c t of c u l t u r a l and
handling p r a c t i c e s on the q u a l i t y o f sweet potatoes.
t or s have reported on the infl ue nc e of c u r i n g ,
Several
investiga­
s t o r i n g , cooking tempera­
t ur e and cooking time on the q u a l i t y of baked sweet potato roots
43, k k ,
57, 58, I k ,
8 5 , 92, 9 5 ) -
In general
(*t0,
they have shown t h a t cu r­
ing improves the e a t i n g q u a l i t y o f the roots and most v a r i e t i e s continue
to improve f o r a time
in storage.
In the pas t, curing periods of up to
15 days have been recommended but c u r r e n t recommendations are f o r k to
6 days o f curing a t 85° F. when harvested during warm weather ( 8 ) .
ing,
Cur­
to enhance the h e a li n g of wounds, combined w it h storage a t 55° to
6 0 ° F. and high r e l a t i v e humidity has been shown to be conducive to
c e r t a i n changes which occur in the carbohydrate content of the sweet
p ot at o.
There was an increase in t o t a l
ing and f o r the f i r s t
s ta rc h con ten t.
Hines
and reducing sugars during c u r ­
3 months o f storage coupled wit h a decrease
(50),
Jenkins e_t a_l_ ( 5 7 ) , Massey and his
in
16
co-workers
(67) and Hammett (40) working independently have shown a
close c o r r e l a t i o n between the area of production and the q u a l i t y of
baked and/or canned roots.
Baumgardner and Scott
ness of processed sweet potatoes.
(12)
studied the f i r m ­
They were able to infl uen ce the f i r m ­
ness of a given v a r i e t y by simply va ry ing the holding temperature of the
f r e s h l y harvested root s,
Jenkins (57)
reported t h a t the q u a l i t y o f the
baked roots was influenced by the temperature and du r a t i o n of the baking
process.
He concluded t h a t baking the roots f o r 90 minutes a t 350° F.
was more f a v o r a b l e f o r a high q u a l i t y product than baking f o r sh o rte r
periods a t highe r temperatures.
Ali
(1) st a t e d th a t 375° F.
f o r 75
minutes was b e t t e r than lower temperatures.
Several workers have reasoned t h a t q u a l i t y
te ris tic
is a h e r i t a b l e charac­
in the sweet potat o although t h e i r data to support such a con­
c l us io n were very l i m i t e d
(1,
24, 49, 67, 68,
106).
A number o f workers
have considered from one to a very few of the q u a l i t y f a c t o r s .
The
p r i n c i p a l ones considered have been carotene and dry m at ter con ten t.
The work of Hernandez (49) and of Constantin
most comprehensive on o v e r a l l q u a l i t y and I t s
(24) has perhaps been the
inheritance.
was concerned p r i m a r i l y w i t h carotene and dry matter
in the area of
ch ara ct ers g e n e r a l l y considered as a f f e c t i n g e a t i n g q u a l i t y .
(24)
Hernandez
Constantin
studied carotene and solu ble s o li d s and baking q u a l i t y as measured
by a baking index.
Color, f l a v o r ,
texture, f ib e r,
ness were considered as components o f q u a l i t y
sweetness and moi st ­
in the baked roots and
each component was assigned a maximum value of 10.
He s u b j e c t i v e l y
r ated the i n d iv id u a l seedlings f o r each f a c t o r and obtained a baking
index as an average o f the scores f o r the various components of q u a l i t y .
The data of Hernandez (49) and Constantin
(24) did show t h a t q u a l i t y
is
17
a strongly h e rita b le character.
Baumgardner (2) and others
(40, $2)
have suggested t h a t po s si b ly p a r t o f the q u a l i t y complex was i n h e r i t e d
as an enzyme system capable o f br i n g in g about desired star ch conver­
sions or ot her changes under f a v o r a b l e co n d it io n s .
F i ber
One of the q u a l i t y c h a r a c t e r i s t i c s of the sweet potat o t h a t was r e ­
cognized e a r l y
in e f f o r t s
the f l e s h y roots
(13,
to improve the crop was the f i b e r content of
10 6) .
Fiber
in the sweet potat o root
is due to
the development of tough and o f t e n coarse strands of f i b r o v a s c u 1ar
t i s s u e , which according to Hayward (46) may be d i s t r i b u t e d throughout
the ro ot t i s s u e .
E a r l y workers
(16,
19, 56,
113) recognized t h a t roots
w i t h a high f i b e r con ten t were not acceptable as a baked or canned pro­
du c t.
Sweet po ta to breeders have attempted to avoid the re le as e of a
new v a r i e t y high in f i b e r by s e l e c t i n g only those i n d i v i d u a l s t h a t ex­
h i b i t e d a low f i b e r c o n te n t.
Several workers have noted an apparent in ­
f lu e n c e of environment on the f i b e r content
(16, 41, 50, 56,
113).
In
1959, Newsom (77) described a method f o r determining the f i b e r content
o f baked sweet po ta to r o o t s .
Harmon (42)
studied the f i b e r content of
c e r t a i n sweet potat o v a r i e t i e s and s ee d lin g s .
among see dlings and v a r i e t i e s
fibers.
ronmental
tin
in the q u a n t i t y , co lo r and t e x t u r e of
He suggested t h a t f i b e r ,
factors,
He found a wide v a r i a t i o n
although st r o n g l y
in flu enc ed by e n v i ­
Is d e f i n i t e l y a h i g h l y h e r i t a b l e c h a r a c t e r .
Constan­
(24) ev a lu a te d a number o f seedlings f o r f i b e r content from a sub­
j e c t i v e view.
He did not discuss f i b e r content as such, but he con­
s id ere d i t only as i t
in flu enc ed his baking index.
His data showed
some ap p re c ia b le v a r i a t i o n among and w i t h i n progenies
Stokes
(102)
reported
in f i b e r con ten t.
in 1934 t h a t t h e r e was an a s s o c i a t i o n between
18
fib er
in sugar cane and the per cent sucrose,
di am et er , hei ght and weig ht.
orde r but s i g n i f i c a n t .
internode le n g t h ,
stalk
The c o r r e l a t i o n was p o s i t i v e and of a low
Wang (107) found t h a t sucrose and f i b e r content
o f sugar cane v a r i e d s i g n i f i c a n t l y w i t h i n a v a r i e t y among p l o t s and
years which i n di c at ed a very strong environmental
(k j)
influence.
Hebert
concluded b r i x and sucrose were c l o s e l y c o r r e l a t e d and independent
of s t a l k diameter and e r e c tn e s s .
He reported a close a s s o c i a t i o n be­
tween c h a r a c t e r i s t i c s o f parents and t h e i r progenies but expression of
t h i s ch a ra ct er was s t r o n g l y
gre ga tio n in a l l
influenc ed by seasons.
Tran s gr es si ve se­
crosses was evidenced by the number of
bove and below e i t h e r p a r e n t .
Singh (9*0
i n d i v i d u a l s a-
reported a s i g n i f i c a n t po s i­
t i v e c o r r e l a t i o n between per cent f i b e r and per cent bagasse and also
between per cent f i b e r and sucrose co n te n t.
He st a t e d t h er e was a close
r e l a t i o n s h i p between the f i b e r content of parents and progenies and
t h a t wit h a knowledge o f the f i b e r content of the pa r e n ts , one could
r e l i a b l y p r e d i c t the f i b e r content of progenies; however, some t r a n s gress ive segregation did occur.
He said f i b e r was a q u a n t i t a t i v e cha­
r a c t e r w it h an absence of dominance among the genes;
selection for
in itia l
low f i b e r or high sucrose should not be too r i g i d .
Richmond ( 86)
in his study of l i n t q u a l i t y
in American upland
cotton suggested two g e n e ti c systems were involved - presence or absence of
Lewis (65) found a l l
lity
therefore,
l i n t and m o d i fi e r s f o r q u a n t i t y and q u a l i t y .
F3 progenies were ex tr em el y v a r i a b l e
in his study of Gossypiurn hy b rid s.
range of v a r i a t i o n
a s i n g l e gene f o r
in l i n t s t r e n g t h ,
of upland cotton v a r i e t i e s .
in l i n t qua­
Green (37) described a wide
length and fineness
S e l f and Henderson (93)
st re ngt h of the f i b e r behaved as a t y p i c a l
in a c o l l e c t i o n
re por te d t h a t
q u a n tita tiv e character.
They
19
st at ed the mean d i f f e r e n c e between the 2 parents
probably due to A or 5 p a i r s o f genes.
length
in t h e i r study was
Sloan (98) concluded t h a t f i b e r
in American upland cotton was a h i g h l y h e r i t a b l e ch a ra c t e r con­
d i t i o n e d by a t
l e a s t 3 p a i r s of genes.
Stafford
(100)
stated f ib e r
st re ngt h and pe r im et e r h e r i t a b i l i t y was approximately 50 per cent and
was c o n t r o l l e d by r e l a t i v e l y few genes.
Kramer, ert aj_ (62 , 63) developed an o b j e c t i v e method f o r deter min­
ing the f i b e r content of processed asparagus.
This method was shown to
c o r r e l a t e extr em el y w el l w it h s u b j e c t i v e e v a l u a t i o n of asparagus f i b ­
rousness.
S c hm itt , W il d e r and Kramer (91)
in d ic a t e d t h a t the break­
p o i n t between acceptable and unacceptable asparagus from the standpoint
o f fibrousness was a t the app ro xi m at el y o n e - h a l f per cent le ve l ov f i ­
ber con tent.
MATERIALS AND METHODS
Source of M a t e r i a l
Fourteen pa re n ta l
t h i s study.
lines o f known c o m p a t i b i l i t i e s were selec ted f o r
The p ar en ta l
li n e s were a l l
Louisiana A g r i c u l t u r a l
E x pe r i­
ment S t a t io n v a r i e t i e s or F] see dling s except Kandee, W h i t e s t a r , an
Oklahoma A g r i c u l t u r a l
Experiment S t a t i o n F] se ed lin g
North C a r o li n a Experiment S t a t i o n v a r i e t y ,
l in e s were tr a n s p l a n t e d to
the breeding nursery o f the Louisiana A g r i c u l t u r a l
Experiment S t a t io n
campus a t Baton Rouge, Louisiana
in A p r i l of 1963•
The p l a n t s were t r a i n e d onto a s i x f o o t net w ire t r e l l i s
was c o n t r o l l e d by pruning the top system.
as needed to keep the plants
in a moderately vigorous growing co n d it io n .
p o l l i n a t i o n of the se le c t e d pa r e n ta l
ber and continued to October 2 5 t h .
cut
and growth
I r r i g a t i o n water was app lied
Most p l a n t s had begun f lo w e r i n g by mid-August.
ter)
and a
Nugget (NC171).
Well e s t a b l i s h e d p la nt s o f the pa re n ta l
located on the L. S. U.
(0K5I),
The c o n t r o l l e d cross
l in e s was begun in e a r l y Septem­
Giant soda str aws ,
(7 mm in diame­
in lengths of appro xim at el y two inches, were used t o p r o t e c t
both male and female flow er s from contamination by in se ct s.
Flowers
se le c t e d f o r use as females were emasculated in the l a t e af te rn oon of
the day p r i o r to opening and the exposed p i s t i l was covered w i t h a
s e c ti o n o f soda straw closed a t one end.
Flowers to be used as the
males were se le c t e d a t the same time but were covered wi thou t emascula­
tion.
Female flo w er s were cross p o l l i n a t e d the f o l l o w i n g morning be­
tween 5: 0 0 and 8 : 0 0 a . m . ,
tagged to i d e n t i f y parentage, and re-covered
20
•
21
w it h the soda straw s e c ti o n s .
Seed were harvested as they became dr y,
separated as to parentage, cleaned, placed in marked coin envelopes,
and placed in storage.
In January 1964,
the seed were s c a r i f i e d 20 minutes
in c o n c e n t r a t ­
ed s u l f u r i c a c i d , washed in tap w a t e r , d r i e d , and tra ns po rt ed to the
Sweet Potato Research Center a t Chase,
Lou isiana.
They were plant ed in
the greenhouse benches a t Chase where the seedlings were grown u n t i l
May 13,
1964.
They were then t r a n s p l a n t e d to the f i e l d on rows fo ur
f e e t a p a r t and
the p l a n t s were spaced f i v e f e e t a p a r t on the rows.
The p la nt s were allowed to grow u n t i l September 16,
The roots were harvested September 16,
1964.
1964, counted, placed
in
paper bags t h a t
were coded to i d e n t i f y the parentage and the roots
each p l a n t were
kept s e p a r a t e l y .
of
The roots were c a r r i e d by t r u c k to
the sweet po t at o cu r in g and storage f a c i l i t i e s
U n i v e r s i t y , S t a t e C o ll e g e , M i s s i s s i p p i ,
a t M i s s is s ip p i
St at e
cured f o r seven days at 85
degrees F a r e n h e i t and 85-95 per cent r e l a t i v e humidity and then stored
f o r 30 days a t 60 degrees F a r e n h e i t and 75-85 per cent r e l a t i v e l y hu­
m idity.
All
sampling was c a r r i e d out in arandom manner w it h o u t
ledge of the parentage of
know­
any sample.
Measurements o f the Raw Roots
A l l enlar ged roots of a sample were washed, d r i e d ,
and the skin
co l o r determined under l i g h t from a n o r t h e r l y d i r e c t i o n using the USDA
Standard Skin Color c h a r t
and d i r e c t i o n s f o r
Yeatman ( 1 1 6 ) .
o f each s e e dl in g were grouped in one of the
The roots
f i v e skin c o l o r groups, cream ( C r ) , Tan ( T ) ,
i t s use as
prepared by
Copper ( C u ) , Rose ( R ) , or
Purple (P) but were not separated i n to the sub-groups w i t h i n a given
c o l o r cl ass as i l l u s t r a t e d
in Pl a t e
1.
PLATE 1:
The Sweet Potato Skin Color Scale, Prepared by
the United St a t e s Department of A g r i c u l t u r e in
Cooperation w i t h the Sweet Potato C o ll a b o r a t o r s
Conference, Represents from L e f t to R i g h t :
Pu rp le , Rose, Copper, Tan and Cream Colors
23
Root shape was determined f o r a gi ven see dli ng by o b t a i n in g the
average length and width of a l l
le n g t h r w id t h r a t i o
the roots from t h a t p l a n t , and the
(L:W r a t i o ) was used as the shape index.
and w id t h measurements were made t o the nearest 1/4
measured p a r a l l e l
inch.
All
length
Length was
to the d i r e c t i o n of elongated growth t a k i n g in to con­
s i d e r a t i o n any c ur va tu r e
in c e n t r a l a x i s of the r o o t .
The p o i n t of
maximum diameter was used to determine width.
Dry m at te r content o f each s ee d lin g was determined.
A plug of ap­
p r o x i m a t e ly 20 grams of t i s s u e from the median region of the r o o t ' s
length was ob t a in e d using a number 10 cork b o r e r .
placed
mined.
in pre-weighed, coded, metal cans, and the f re sh weight d e t e r ­
The cans were uncovered, placed
24 hours a t 105° Ce ntigrade,
cool.
The plugs were
in an e l e c t r i c oven, d r i e d f o r
covered, and placed in a d e s ic c a t o r to
The c o n t a i n e r s were then re-weighed and the per cent dry matter
calculated.
Roots of each see dling were ev a lu a te d f o r smoothness or freedom
from v e i n i n g and crac king .
ed w i t h a value o f
s c a le
An a r b i t r a r y scale o f
1 to 5 was e s t a b l i s h ­
1 being very rough and 5 being very smooth.
is i l l u s t r a t e d
in P l a t e 2.
The
Roots of each seedling were also
e v a lu a t e d f o r u n i f o r m i t y o f shape and smoothness using a s i m i l a r a r b i ­
t r a r y scale where
1 represented very v a r i a b l e o r rough and 5 very u n i ­
form root s.
The thickness of the c o r t e x , which according to Hayward (46)
t h a t t is s u e
is
l y i n g between the periderm and the o u t e r cambium and some­
times r e f e r r e d t o as the p e r i c y c l i c zone, was determined to the nearest
1/16 o f an inch.
Carotene was determined by a m o d i f i c a t i o n o f the method o f
PLATE 2
The Scale Used f o r Smoothness of Root Surface.
Ratings were, by Columns, L e f t to Righ t: 1,
2, 3 i ^ and 5 R e s pe c tiv el y
Thompson'and Kon as described by Goodwin ( 3 6 ) .
A one gram sample of
t is s u e was blended 5 minutes
in acetone,
placed on a sucrose column.
The column was washed w i t h 100 ml. of a
2 per cent acetone
in hexane s o l u t i o n .
t r a n s f e r r e d to hexane and
The e l u t e d pigment was c o l l e c t ­
ed and l i g h t absorption determined by reading w it h the Spec tron ic 20 at
450 m i l l i m i c r o n s .
The pigment c o n c e n t r a ti o n was then determined by
l o c a t i n g the abs or pt io n po in t on a standard curve p l o t t e d from samples
o f known c o n c e n t r a ti o n s .
Measurements o f Baked Roots
One root from each p l a n t o f each progeny was baked 90 minutes a t
375° F . ,
cooled f o r 45 minutes a t room temperature and e v a lu a te d .
Whenever p o s si b le roots of a r e l a t i v e l y uniform s i z e
(1 3 / 4 to 2 1/2
inches in diameter and 4 to 7 inches in length) were baked.
Firmness was measured using the ASCO firmness meter w it h a non­
l i n e a r pr es tr es s weight of 500 grams and a n o n - l i n e a r t e s t weight of
400 grams in p o s i t i o n number two.
and the d i a l
scale o f
A t e s t time of
10 seconds was used
reading a t the end of the t e s t period was converted t o a
1 to 5 w it h
1 rep re s en tin g the f i r m e s t and 5 the s o f t e s t roots.
F i b e r was determined a f t e r the method of Newsom (77) w it h m o d i f i ­
cations.
A 25 gram l o n g i t u d i n a l
f o r 20 minutes
s e c ti o n o f the baked root was b o i le d
in 60 ml. of a 10 per cent NaOH s o l u t i o n and poured on
a 3 1/4 inch d ia m et er , 30 mesh screen o f monel w i r e c l o t h w i t h open­
ings app roximately 590 microns wide and washed in tap water to remove
all
tra ces of f l e s h .
The f i b e r s were placed on f i l t e r paper, d r i e d 24
hours a t 100° C . f weighed and the per cent f i b e r c a l c u l a t e d .
the i n d iv id u a l
f i b e r s was rated as i l l u s t r a t e d
in P l a t e 3.
Size of
PLATE 3:
The F ib er Diameter Scale as I l l u s t r a t e d
is Represented by Values:
Top Row: ( L e f t
to Ri ght )
1 = Very Coarse, 2 = Coarse;
Bottom Row:
3 = Medium, k = F i n e , and
5 = Very Fine ( 1. 5 Times Actual S iz e)
27
Color
i n t e n s i t y and u n i f o r m i t y , moistness,
sweetness and f l a v o r
were e v a l u a t e d by a panel o f three and r a t e d on a s ca le o f 1 t o 10
w ith
10 r e p r e s e n t i n g the i d e a l .
A fin a l
r a t i n g f o r each f a c t o r was
o bt ai ne d by a ve r ag in g the scores o f the th r e e p a n e l i s t s .
The baking
index f o r a s e e d l i n g was o bt ai ne d by an average o f the scores f o r
each f a c t o r con si d er ed .
Progeny means were c a l c u l a t e d .
RESULTS AND DISCUSSION
The breeding parents and the expression o f t h e i r ch ar ac te rs are
shown in Tables 1 and 2.
were shape (L:W r a t i o ) ,
per cent dr y matter,
ness, f l a v o r ,
in Table 1,
The c ha ra ct er s ev a lu a te d in the raw roots
smoothness, cortex thick nes s,
skin color,
sweetness,
carotene co n te n t,
and in the baked roots c o l o r , m oi st ­
firmness,
fib e r,
and baking index.
smoothness o f the roots va r ie d l i t t l e
As shown
among the parents due
to s e l e c t i o n pressures f o r t h is c h a r a c t e r e x e r te d through the years.
Root shape o f the paren ts var ie d c on si d er ab ly as shown by L:W ra tio s
o f 1.6 t o 3-**.
The i d e a l
root shape as expressed by the L:W r a t i o has
been considered by sweet potato breeders to be approximately 2. 0 which
means t h a t
the roots a r e twice the
length o f the g r e a t e s t diameter.
The sweet potato parents v a r i e d
tissues o f the roots;
f o r example,
in thickness of the c o r t i c a l
the c o r t i c a l
tiss ues o f the f l e s h y
roots of L3-93 were found to be 1/ 16 of an inch t h i c k , whereas, several
o f the o t h e r breeding parents were 3/ 16 of an inch t h i c k .
In g e n e r a l,
roots w it h a t h i c k c o r t e x have been found to be u n s a t i s f a c t o r y from a
h orticultural
s t a n dp oi nt .
The ca ro te ne c o n te n t of the sweet po t at o parents,
m i l l ig r a m s per 100 grams o f f re sh root t i s s u e ,
( W h it e s t a r )
to a high o f
19-** ( L8—3) •
as expressed in
var ie d from a low of 0 . 7
The dry matter content of L l - 8 0 ,
the hi gh es t parent, was appro xim at el y 50 per cent g r e a t e r than L 1—171>
the lowest.
The s k i n color o f the roots o f the d i f f e r e n t parents varied from a
28
TABLE 1:
Parent
Shape
( L:W Ra tio )
A De scr ip tio n o f the Characters of the Raw Roots
of 14 Sweet Potato Breeding Parents
Smoothness-^/
Cortex
Thickness in
1/16 inches
Carotene
Content
(mq/ 1 0 0 qms)
Per Cent
Dry
Matt er
Skin
Col or
L3-77
1.99
4.9
2.0
18. 1
28.34
Copper
Kandee
1.89
4 .1
3.0
6.2
28.19
Tan
Whi t e s t a r
2.44
3.2
2. 0
0. 7
28.30
Cream
L3-80
2.00
4.4
3.0
9.6
29. 84
Rose
L3-93
3.50
4.0
1.0
15.2
25.24
Copper to Rose
L3-77t
3.25
4.8
2. 0
17.0
22.89
Rose to Copper
LI 31
3.43
3.3
3.0
8.6
29.34
Tan
L8-3
2.38
4.9
2.0
19.4
26.56
Rose to Copper
LI -171
3.00
3.9
2.0
14.9f
20.73
Rose
OKS 1
2.67
4.8
2. 0
11.6
26.21
Copper
L9-39
1.60
4.5
3.0
12.1
23.86
Copper to Rose
L I -80
3.20
3.9
3. 0
15.2
30.51
Copper
NCI 71
3.00
4.8
3. 0
10.8
23. 09
Copper
L21
2.33
4.3
2.0
2.9
32.22
Tan
]_/ Numerical scale from 1 to 5*
1 = Very rough, 5 = Very smooth.
TABLE 2:
Parent
A D e sc ri pt io n of the Characters of the Baked Roots
of 14 Sweet Potato Breeding Parents
.............
” " CUL'OR
1ntens i ty \J Uni formi ty_l_/
Moi s t nessj_/
F 1avorJ_/
Sweet­
ness^/
F i rmness2/
TIBER'
"
S i z e V Per Cent
Baki ng
1n d e xj /
L3-77
7.9
7. 5
7-0
7.3
7. 0
4.4
2. 5
0.631
7.3
Kandee
2.5
3. 0
4.5
5.0
5. 5
3. 0
3.2
0.301
4.5
Whi t e s t a r
1.0
8.5
2.5
4.0
3. 5
1.0
2.4
0.741
00•
L3-80
4.0
5.5
6.4
6.5
6.7
3.0
4.9
0.663
6.2
L3-93
7.0
5.6
7.4
7.6
6.4
3.7
4.1
0.503
6.9
L3-77t
7-5
8.0
7.1
7.4
7.5
4.6
4.0
0.483
7-7
LI 31
5.0
4.1
5.5
2.1
3.4
1.6
2.2
0. 746
4.0
L8-3
8.1
8. 2
7. 5
8.0
7.5
4.6
2.8
0.775
7.8
LI-171
6.4
7.3
7.1
5.7
6.4
3.5
3.1
0.715
6.6
0K5I
5.5
7.1
8.4
6.5
7.0
4.5
3. 0
0. 489
7.0
L9-39
6.1
4.6
8.5
6. 5
6.5
4.5
2.7
0. 959
6.6
L I - 80
5.8
7.5
8.3
6.6
8.0
4.6
4.2
0. 628
7. 5
NC171
3-6
5.5
5.1
5.5
4.6
2.5
2.1
1.106
4.8
L21
1.0
7.6
4.5
4.5
6.4
1.5
3.9
0.741
4.9
\J
2J
j}/
Numerical scale
Numerical scale
Numerical scale
from 1 t o 10;
from 1 to 5:
from 1 to 5:
I = Least d e s i r a b l e , 10 = Most d e s i r a b l e .
1 = Very f i r m , 5 * Very s o f t ,
1 = Very coarse, 5 = Very f i n e .
31
cream to a rose c o l o r .
D i f f i c u l t y was encountered in some cases,
d i s t i n g u i s h i n g between the copper and rose c l as se s.
Some pa re n ta l
in
l in e s
were c l a s s i f i e d as copper to rose or rose to copper skin co lo r depending
on which c o l o r tended to be predominant.
Data o f the baked roots o f the p a r e n ta l
l i n e s , as shown in Table 2,
v a r i e d con si d er ab ly
in some of the ch a ra ct er s c o n t r i b u t i n g to the baking
index.
in carotene and f i b e r content were larg e among the
Differences
breeding p ar en ts .
NC171 contained more than 4 times as much f i b e r as
Kandee.
The baking index, which is the average expression o f a l l
te r s o f the baked r oo ts ,
the charac­
v a r i e d much less than the o t h e r c h a ra c t e r s .
This was accounted f o r by the f a c t t h a t a parent may be r e l a t i v e l y poor
in a c e r t a i n c h a ra c t e r f o r baking because i t was se le ct ed f o r the s u p e r i ­
or expression o f another c h a r a c t e r and t h a t tended t o narrow the v a r i a ­
t i o n among the pa r e n ta l
lines.
A summary o f the production o f storage roots by each se e dl in g
each progeny and the per cent t h a t r o t t e d
Table 3.
The p a r e n ta l
in st orage
is presented
in
in
l in e s were crossed in 21 d i f f e r e n t combinations
and the number of seedlings o b t a i n e d ,
the number and per cent t h a t de­
veloped storage r o o t s , and the per cent o f seedlings w it h roots t h a t
rotted
in storage are shown f o r each of 21 progenies.
The per cent of
seedlings t h a t produced storage roots v a r i e d from 21 .5 f o r the Kandee
s e l f e d progeny to 87-5 f o r the L8-3 x L I —80 progeny.
The Kandee s e l f e d
and the 0K51 x L131 progenies were l e a s t produ ctive w i t h an average of
3 . k roots per se e dl in g w h i l e the L3-80 x L3-77 progeny produced an
average o f
11.3 roots per s e e d li n g .
various progenies
in which a l l
The per cent of seedlings
o f the roots r o t t e d
in the
in storage v a r i e d
32
TABLE 3:
The E f f e c t of Parentage on the A b i l i t y o f
Seedlings in Each Progeny to Produce Roots
th a t Store Wei 1
Number
of
Seed1 i nqs
Cross
No. Seed1 i ngs
Produc i ng
Storage
Roots
Per Cent
Seed 1i ngs
Producing
Storage
Roots
Average
Number
Roots/
Seed1 ings
Per Cent
Seedli ng
Roots Rot­
ted i n
Storaqe
L3- 8 0 x L3-77
18
10
55 .5
11.3
0
L3-77 (X)
38
20
52 .6
4.2
30.0
L3-77 x NCI71
79
21
26.6
3.5
14.3
L3-80
44
16
36.it
4.4
43.8
35
19
54 .3
4.2
21.0
135
29
21.5
3.4
17.2
L 3 - 7 7 t x L131
73
2b
32.9
4.6
25.0
L3-77 x L I - 80
80
38
47.5
4.8
15.8
L3-77 x K
53
b\
7 7 -b
4.2
26.8
172
138
80 .2
4.5
23.9
L3-80 x K
60
27
66.7
10.0
25.0
K x L3-80
16
10
62.5
8.5
30.0
K x L3-77
18
12
66.7
10.0
25.0
L3-93 x L I3 I
93
58
62.b
4.7
18.9
120
90
75 .0
5. 0
15.6
L8-3 x L I -80
40
35
87 .5
5-5
2. 9
LI -171
X
21
10
47.6
4.4
20.0
L131
L3-77
46
33
71 .7
5.2
21.2
Mb
5b
22.9
3.4
27.7
L9-39 x NCI71
21
1
33.3
4.6
28.6
W . S . * x L21
45
27
60.0
4.8
18.5
(X)
L 3- 77 t x NCI71
Kandee (K)
(X)
L3-77 x L3-80
L3-93 x L I - 80
X
LI 31
0K51 x L I 31
* W,S. = W h i t e s t a r
33
from z e r o to 4 3 . 8 .
The performance of the 14 parental
is presented in T a b l e 4.
l i n e s as male or female parents
The parent L8- 3 ( J u l i a n ) had the best p e r f o r ­
mance as a female from the st and po int o f the per cent of the see dlings
in t h e progeny t h a t produced storage roots and roots t h a t stored w e l l ,
whereas 0K51, L 9 - 3 9 and Kandee were poorest as female pa re n ts .
When
used as the male pa re n t, L3-80 produced the g r e a t e s t per cent o f seedl i n g s w i t h en la rg ed storage root s and NC171
Only four o f
the f ou rte en parents,
were used as both male and fe m a le .
in a l l
(Nugget) had the l e a s t .
L3- 77, L3-80,
Kandee,
L131 and Kandee,
L3-77 and L3“ 80 were crossed
possible combinations w i t h one a n o th e r.
Kandee, L3-80,
and L 131
produced a somewhat smaller average number of roots per p l a n t as a male
parent
than as a female p a r e n t ,
however,
the reverse was tru e f o r 1-3-77.
L3-80 and Kandee progenies produced a g r e a t e r per cent o f the p la nt s
w i t h enlarged s t o r a g e roots when they were used as male pa re n ts .
The
opposi t e was t r u e f o r L131, b u t L3-77 performed e q u a l l y w el l as a male
or f e m a l e parent.
The p o s si b le presence o f cytoplasmic f a c t o r s was
suggested by these data but t h e y were not s u f f i c i e n t to support the
cy t o p la sm ic t h e o r y .
I nh er i tance of Shape
The frequency d i s t r i b u t i o n of the sweet potato see dli ng o f each
progeny into d i f f e r e n t
le n g t h - w i d th r a t i o classes
and t h e per cent o f the see dling s
in each class
The progeny means vari ed from 1.54 to 3 . 0 3 .
is given in Table 5
is shown in Table 6 .
In most progenies more than
60 p e r cent of th e seedlings were in classes 3, 4 and 5» possessing a
L:W r a t i o of 1.5 to 3. 0.
However, the progeny o f L3-77 * L l - 8 0 had only
TABLE 4:
Parental
Females:
Line
L3“ 77
L3-80
Kandee
LI 31
L3-93
L3-77t
L8-3
LI -171
0K51
L9-39
Wh ite s ta r
Comparative Data of Seedlings when Parents Used as a
Male or Female
Number
of
Proqen ies
5
3
3
1
2
2
1
1
1
1
1
Number
Seed1 i nqs
Number
Seedli ngs
Producing
Roots
Per Cent
Seedli ngs
Produc i ng
Roots
Average
Number
Roots per
Seedli nq
Per Cent
Seed 1i ngs
w ith Roots
th a t Rotted
422
122
169
46
213
108
4o
21
124
21
45
258
53
51
33
148
b3
35
10
54
7
27
61.1
43.4
30 .2
71.7
69.5
39 .8
87.5
47.6
22 .9
33-3
60.0
4.4
6.1
5.9
5.2
4.9
4.4
5.5
4.4
3.4
4.6
4.8
22 .9
16.7
21.5
21 .2
16.9
23.3
2.9
20.0
27.7
28 .6
18.5
120
232
248
311
240
135
45
75
164
97
146
163
47
27
62.5
70.6
39-1
46.9
67-9
34 .8
60 .0
6. 5
4.7
4.2
4.2
5.1
3.9
4.8
21.3
26.2
18.5
23.2
12.9
19.1
18.5
21
Males:
L3-77
L3-80
Kandee
LI 31
L I -80
NCI 71
L21
4
3
3
4
3
3
1
.
21
V>3
45*
TABLE 5:
Class No.
1
O
L:W Ratio
•
1
LTV
«
2
LA
•
1
O
Frequency D i s t r i b u t i o n o f Number Sweet P o ta t o S e e d li n g s o f Each
Progeny i n t o D i f f e r e n t Le n g th rW id th R a t i o Classes
3
4
5
6
7
8
9
10
0•
tn
0
-3"
1
in
in
■31
0
0
m
1
in
0*
in
10
>
0
0
LTV
CM
CM
LTl
*
O
1
1
1
Lf\
-3-
1
2
1
b
2
2
3
10
3
2
4
3
it
2
3
9
5
5
10
9
9
5
4
4
7
11
3
CM
L3-80 x L3-77
2
4
1
7
14
L3-77 (X)
1
9
L3-80 (X)
L3-77t x L131
Kandee (X)
L3-77 x L I -80
1
0
oa
•
ro
Parentage
L3-77 x NC171
«
3’
3.00
0. 42
1.87
0.21,
2. 76
0.37
2.15
0. 33
1.78
0.23
2. 67
0. 32
1.89
0.19
b
2.4it
0. 16
1
2.5*+
0.31
2.16
0.32
1
1
1
2
6
16
10
5
1
1
L3-77 x L3-80
I
6
39
36
25
12
8
L3-80 x K
1
4
5
9
7
1
1
3
1
1
1
3
6
Standard
Error
0.43
3
1
Progeny
Mean
3.03
1
L3-77 x K
K x L3-77
-
Continued
TABLE 5:
C lass No.
L:W R a t io
Continued
1
2
3
4
5
6
7
8
9
10
o
LTV
O
LA
o
o
1
1
LA
O
-3"
i
LA
LA
o
-3"
1
LA
CM
o
cn
i
LA
CM
CM
Cvl
•
CA
CA
LA
«
ta>
>
o
Progeny
Mean
S ta n d a rd
E rror
1
2. 04
0.74
2.01
0.16
2. 29
0. 15
2.11
0.22
2.01
0.16
2.36
0.28
2.15
0. 22
1.54
0 .19
1.60
0. 62
1
LA
*
1
O
1
»
Parentage
LTV
CA
O
LA
K x L3-80
1
5
1
1
1
L3-93 x L131
9
22
13
9
4
1
8
20
29
20
8
2
4
12
10
6
2
4
6
1
12
8
5
2
4
10
5
4
L3-93 x L I -80
1
L8-3 x L I -80
Ll-171 x L I 31
L I 31
X
L3-77
0K51 x L I 31
1
7
17
8
W.S. x L21
2
12
7
6
L9-39 x NCI71
1
3
1
2
O
•
1
1
1
1
1
1
TABLE 6:
Class
1
o
—
I
Parentage
Percentage o f Sweet P o ta t o S e e d li n g s o f Each Progeny
In D i f f e r e n t L e n g th rW i d th R a t i o Classes
2
3
LTV
4
O
O
LA
I
»
»
CM
c \l
i
l
i
O
Ln
O
IA
_•
J
^
^
L3-77 (X)
2.5
6
—
22.5
L3-80 (X)
«
ro
I
7
•
O
1
LA
OA
CA
o
9
o
•
LA
1
LA
-d’
10.0
20.0
10.0
5. 0
35 .0
20 .0
10.0
10.0
15.0
35. 0
25.0
7.5
5. 0
25.0
18.8
25. 0
12.5
20 .8
10
a.
=>
i
o
LA
5.0
2.5
18.8
37.5
20.8
Kandee (X)
34.5
31 .0
31.0
L3-77 x L I -80
13.2
10.5
10.5
18.4
28 .9
7. 9
4.2
4.2
3.4
L3-77 x K
4.9
14.6
39.0
24.4
12.2
2.4
2. 4
L3-77 x L3-80
0.7
4.3
28.3
26.1
18.1
8.7
5.8
L3-80 x K
3.7
14.8
18.5
33.3
25 .9
58.3
8.3
25.0
8.3
50.0
10.0
10.0
10.0
10.0
•
-di
40.0
12.5
K x L3-80
LA
•
OA
1
O
L3-77t x L131
K x L3-77
8
20.0
L3-80 x L3-77
L3-77 x NCI71
U"\
5
2.9
7-9
0. 7
4.3
2.9
3.7
10.0
Cont i nued
VjJ
TABLE 6 :
Class
1
O
*
Parentage
1
LA
*
L3-93 x L131
L3-93 x L l-8 0
1.1
L8-3 x L I -80
2
3
4
LA
—
1
O
O
04
1
LA
—
—
LA
CM
8
O
CM
cn
1
LA
CM
15.5
37.9
22.4
15.5
6.9
1.7
8.9
22.2
32.2
22.2
8.9
2.2
34.3
28.6
17.1
•5.7
40.0
60.0
3.0
36.4
24.2
15.2
6,1
12.1
18.9
9.4
7.5
11.
Ll-171 x L131
L131 x L3-77
0K51 x L131
1.9
13.2
32.1
15.1
W.S. x L21
7.4
iA .if
25.9
22 .2
14.3
42.9
L9-39 x: NC171
Continued
14.3
5
0
28.6
6
in
PA
O
•
PA
7
0
8
n
j-*
LA
OA
•
1
O
*
■J-
9
0
in1
1
in
J-
1.1
2. 9
3.0
1.9
10
u.
3I
1
O
•
LA
1 .1
3 9 . 4 per cen t of the seedlings
in these classes,
x NC171 had 4 2 . 9 per cent and W h i t e s t a r
The wide v a r i a t i o n
ed in Pl at e 4.
in shape occ ur rin g
(W.S.) x L21 had 48.1 per cent.
in a s i ng le progeny is i l l u s t r a t ­
The progeny mean was i nt erm ed iat e between the 2 parents
in only 2 progenies,
x NC171
L I 31 (3*43)
(3-00) = 2.67.
x L3-77 (1 -9 9 ) = 2 . 3 6 and L3-77 (1 .9 9)
In one progeny,
L9-39 ( 1 . 6 0 ) x NC171
progeny mean was the same as the female parent
L3-77 ( 1 . 9 9 )
A ll
the progeny of L9-39
(3.00),
the
and in the progeny of
x Kandee ( 1 . 8 9 ) the mean was the same as the male pare nt.
progenies
in which L3-80 was e i t h e r the male or female paren t had a
progeny mean g r e a t e r than L3-80.
which L l - 8 0 or L131 were
On the ot her hand, a l l
crosses in
involved as e i t h e r male or female p a r e n t , the
progeny mean was always less than t h a t p a r e n t.
i e s , no d e f i n i t e p a t t e r n occurred.
Some had a
In the remaining progen­
L:W r a t i o g r e a t e r than
the highest parent w h i l e others had a L:W r a t i o sm al le r than the s m a ll ­
e s t p a r e n t, which i n d i c a t e s t r a n s g r e s s iv e s e g re ga tio n .
genes, one f o r
length and one f o r w id t h ,
functioning
Two sets of
independently, pro­
bably c o n t r o l s the shape of the r oo ts .
The c o r r e l a t i o n c o e f f i c i e n t between the number of roots per seed­
l i n g and the shape index or L:W r a t i o
though r was s i g n i f i c a n t the p r a c t i c a l
tremely sm al l.
lity ,
is presented
in Table 35.
A l­
value of t h i s s i g n i f i c a n c e
is ex­
Using the formula r^ x 100 = v a r i a t i o n due to h e r i t a b i -
less than one per cent o f the v a r i a t i o n was due to h e r i t a b i 1i t y .
Thus, the s e l e c t i o n of high y i e l d i n g p l a n t s should not in flu en ce the
shape and a t the same time s e l e c t i o n based on shape o f the roots would
not i n t e r f e r e w it h the s e l e c t i o n of high y i e l d i n g clo nes .
This
indi­
cates no link age between y i e l d i n g a b i l i t y of a see dli ng and shape of
the f le s h y r o o t s .
PLATE k :
V a r i a t i o n s in Shape Observed in the Fj Progeny
of the Cross L3-77 x L3-80.
Lower Row Repre­
sents D e si r a bl e Length:Width R a t i o
k]
t n h er ita n ce o f Smoothness
The frequency d i s t r i b u t i o n o f the seedlings
in each progeny into
d i f f e r e n t classes based on the smoothness o f the su rf ace of the roots
is shown in Table 7 and the percentage of seedlings
given
in Table 8.
in Pl a t e 2.
ing were the reasons f o r p l a c i n g the seedlings
ated.
(classes
is
The data were skewed somewhat toward the smooth
side of. the sca le which is i l l u s t r a t e d
ratings
in each class
Ve ini ng and crack­
in the lower smoothness
1 and 2 ) ; these defec ts however, were not d i f f e r e n t i ­
This d i s t i n c t i o n would have been desirabJe because the vei ni ng
and crac king o f the roots as observed in these progenies were probably
not r e l a t e d .
The r e l a t i v e l y severe c r ac ki ng i l l u s t r a t e d
a p p a r e n t ly g e n e t i c a l l y c o n t r o l l e d .
in P l a t e 5 is
Audus (10) discussed f a c t o r s a f f e c t ­
ing growth in p l a n t s and there a r e no data to prove sweet potatoes
would respond d i f f e r e n t l y .
sim ilar
The d i s t o r t i o n s
illu strate d
in many respects to the responses o f o t h e r pl a n t s t o growth
substances.
Patt er son and Speights
cidence o f cra c ki ng to f e r t i l i z e r s ,
crop r o t a t i o n .
(80) attempted t o r e l a t e the in ­
p a r t i c u l a r l y nitrogenous ones, and
They obtained h i g h l y s i g n i f i c a n t
increases
roots where sweet potatoes were grown in the same s o i l
ye ar s.
in P l a t e 5 are
in cracked
in successive
Observations made of the data in t h i s study i n d i c a t e cracking
is a g e n e t i c a l l y c o n t r o l l e d c h a r a c t e r ,
although some environmental con­
d i t i o n s may promote i t s ex pr es si on.
In a l l o f the obse rv ation s o f t h i s study v e i n i n g was a pp ar en tly
accompanied by an excessive accumulation o f f i b r o - v a s c u l a r t i s s u e
in
the veins which is a p p a r e n t ly g e n e t i c a l l y c o n t r o l l e d and such roots
were observed to be q u i t e f i b r o u s .
The d a t a were not recorded in such
a way t h a t c o r r e l a t i o n s between f i b e r and v e i n i n g could be determined.
TABLE 7:
Class
2
Rough
3
Slightly
Rough
4
Smooth
5
Very
Smooth
Progeny
Mean
Standard
Er ro r
4
1
5
4.1
0.31
2
4
10
3
3.6
0. 23
L3-77 x NC171
3
5
11
2
3.4
0.19
L3-80 (X)
2
5
5
4
3.7
0.25
L3- 77t x NC171
2
7
7
3
3.6
0.21
Kandee (X)
3
9
9
8
KjJ
00
Parentage
1
Very
Rough
Frequency D i s t r i b u t i o n of Number of Sweet Potato Seedlings
o f Each Progeny i n t o D i f f e r e n t Classes Based on Smoothness
o f the Root Surface
0. 1 8
L3-77t x L I 31
5
8
8
3
3.4
0.19
L3-77 x L I -80
1
9
23
5
3. 8
0.11
17
13
4
3.3
0. 15
57
16
3.5
0.08
L3-80 x L3-77
L3-77 (X)
1
L3-77 x K
2
5
L3-77 x L3-80
2
18
L3-80 x K
1
3,
8
12
3
3.5
0.18
2
3
6
1
3.5
0.26
K x L3-77
m
Cont i nued
TABLE 7:
Class
2
Continued
4
Parentaqe
1
Very
Rouqh
Rouqh
K x 13-80
I
I
3
4
L3-93 x L I 31
3
8
27
L3-93 x L I -80
3
6
L8-3 x L I - 80
3
S Ii ghtly
Rouqh
5
Very
Smooth
Progeny
Mean
Standard
Er ro r
1
3.3
0.8 2
12
8
3. 3
0.14
23
36
22
3.8
0.1 1
4
10
17
4
3 -6
0.14
Smooth
LI - 1 71 X LI 31
I
1
5
1
2
3. 2
0.39
LI 31 x L3-77
1
6
10
12
4
3.4
0.18
0K5I x L I 31
4
8
20
12
8
3. 2
0.16
W.S. x L21
I
8
8
8
2
3.1
0. 20
2
3
2
3.0
0.31
L9-39 x NCI71
44
TABLE 8:
Class No.
Percentage of Sweet Potato Seedlings of Each
Progeny in the D i f f e r e n t Classes Based on
Smoothness o f the Root Surface
3
Slightly
Rouah
Smooth
40.0
10.0
50. 0
10.0
20. 0
50. 0
15.0
L3-77 x NCI71
14.3
23-8
52.4
9.5
L3-80 (X)
12.5
31.3
31.3
25.0
L 3- 77 t x NC171
10.5
36.8
36.8
15.8
Kandee (X)
10.3
31 .0
31. 0
27.6
L 3- 77 t x L131
20.1
33.3
33.3
12.5
L3-77 x L I - 80
2.6
23.7
60.5
13.2
Parentaqe
1
Very
Rouah
2
Rouah
L3-80 x L3-77
L3-77 (X)
5.0
4
5
Very
Smooth
L3-77 x K
4.9
12.2
41.5
31. 7
9.8
L3-77 x L3-80
1.5
13.0
32.1
41.6
11.7
L3-80 x K
3.7
11.1
29.6
44.4
11.1
16.7
25.0
50.0
8. 3
10.0
10.0
30 .0
40.0
10.0
L3-93 x L I 31
5.2
13-8
46.6
20 .7
13.8
L3-93 x L I - 8 0
3-3
6.7
25 .6
40.0
24.4
11.4
28.6
48.6
11.4
K x L3-77
K x L3-80
L8-3 x L I - 80
L 1-171 X L131
10.0
10.0
50 .0
10.0
20 .0
L I 31 x L3-77
3.0
18.2
30.3
36.4
12.1
0K51 x L131
7.7
15.4
38 .5
23.1
15.4
W.S. x L21
3.7
29.6
29.6
29.6
7.4
28.6
42.8
28.6
L9-39 x NC171
PLATE 5:
Two Examples o f Severe Cracking o f the Roots
Occurring App ar ent ly E a r l y in the Growing
Season
he
The f a c t t h a t the data were skewed toward the smooth side could e a s i l y
be accounted f o r by the f a c t t h a t a l l
s e l e c t e d f o r smoothness.
the p ar en ta l
l in e s used have been
Consquently, no paren t used in t h i s study had
rough r o o t s .
The c o r r e l a t i o n c o e f f i c i e n t between the number of roots and smooth­
ness (T able 35) was s i g n i f i c a n t but o f very low magnitude.
As shown in
Table 35, th ere was no c o r r e l a t i o n between shape and smoothness.
I n h e r i t a n c e of Cort ex Thickness of Sweet Po tato Roots
The frequency d i s t r i b u t i o n of the see dlings of each progeny in to
d i f f e r e n t classes based on the thickness o f the co r t e x
Table 9 and the percentage o f seedlings
10.
in each class
is presented in
is shown in Table
The class mean of the progenies v a r i e d from approximately 1.9 f o r
the progeny of Kandee x L3-77 to appro xim at el y 3- ^ f o r the progeny of
L9-39 x NCI71•
near,
In most progenies the mean was located between, or very
the mean o f the two p ar en ts .
In two progenies
( W h it es t ar x L21
and L9-39 x NC171) the c l a s s means were a p p r e c ia b ly l a r g e r than the
hig hes t pare nt .
In each progeny t her e were roots w i t h a c o r t e x t h in n e r
than the t h i n n e s t parent and in most pr oge nie s,
c o r t e x t h i c k e r than the t h i c k e s t p a r e n t.
Thi s
th ere were roots w it h a
ind ic at ed most of the
parents possessed genes t h a t were heterozygous f o r c o r t e x thickness and
t h a t segregation was t r a n s g r e s s i v e .
Three of the pa re n ts , Kandee,
crossed in a l l
L3-77 and L3-80, were s e l f e d and
po s si b le combinations w i t h each o t h e r .
When L3-77,
c o r t e x thickness = 2 ( 1 / 8 i n c h ) , was used as the male p a r e n t,
the pro­
geny mean was much nearer the mean j> f L3-77 than t h a t o f the female pa­
rent.
This was suggestive o f a strong p a t e r n a l
in flu en ce but such an
TABLE 9:
Frequency D i s t r i b u t i o n of Sweet Potato Seedlings of Each
Progeny in to D i f f e r e n t Classes Based on Thickness of the
C o rte x* of the Roots
h
]/k"
1
1/16"
2
1/8"
3
3/16"
L3-80 x L3-77
1
7
2
L3-77 (X)
2
9
6
3
L3-77 x NC171
1
13
18
5
11
3
Class
Parentaqe
L3-80 (X)
5
5/ 16"
Progeny Class
Mean
Standard
Er ro r
2.1
0.18
2.5
0. 20
2.8
0.1A
1
2. 5
0.16
2.6
0.13
2. 6
0.19
2.A
0.12
2
Kandee (X)
1
11
15
2
L3- 77t x LI3I
3
11
8
1
L3-77 x L I -80
2
21
12
3
15
17
8
1
2.9
0.13
5
2.6
0. 07
2.3
0. 16
L3-77 x K
1
L3-77 x L3-80
7
55
58
12
L3-80 x K
h
13
8
2
K x L3-77
3
7
2
1.9
0.19
K x L3-80
1
5
k
2. 3
0.21
L3-93 x L131
1
28
22
2.6
0.09
6
Cont i nued
TABLE 9 :
Class
Parentaqe
1
1/16"
2
1/8”
C o ntinued
3
3/16"
4
1/4"
5
5/ 16"
Progeny Class
Mean
Standard
Er ror
L3-93 x L I -80
2
**3
39
6
2.5
0. 07
L8-3 x L l -80
4
23
7
1
2.1
0.11
Ll-171 x L131
1
5
3
1
2. 4
0. 26
L131 x L3-77
2
14
13
4
2. 6
0.14
0K51 x L131
25
21
5
2
2.7
0.11
W.S. x L21
11
12
3
1
2.8
0.15
4
3
3. 4
0.20
L9-39 x NCI71
* Cortex = Tissues between periderm and p e r i c y c l i c zone.
TABLE 10:
Percentage of Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Classes Based on Thickness of Cortex of the
Roots
Parentage
1
1/16"
2
1/8"
3
3/16"
L3-80 x L3-77
10.0
70.0
20.0
L3-77 (X)
10.0
45.0
30 .0
15.0
2.6
33.3
46.2
12.8
73.3
20. 0
6.7
3.**
37 .9
51.7
6.9
L3-77t x L131
12.5
45.8
33-3
4.2
L3-77 x L I -80
5.3
55.3
31.6
7.9
36 .6
41.5
19.5
2. 4
5.1
40.1
42 .3
8.8
3.6
L3-80 x K
14.8
48.1
29 .6
4.9
K x L3-77
25-0
58.3
16.7
K x L3-80
10.0
50.0
40.0
1.8
49.1
38.6
Class
L3-77 x NC171
L3-80 (X)
Kandee (X)
L3-77 x K
L3-77 x L3-80
L3-93 x L131
............... 7 ...............
1/4"
10.5
Cont i nued
5
5/16"
5.1
4.2
TABLE 10:
Class
Continued
1
1/16"
2
1/8"
3
3/16"
b
1/4"
L3-93 x L l -8 0
2.2
47.8
43.3
6.7
L8-3 x L l-8 0
11.4
65.7
20.0
2.9
Ll-171 x L131
10.0
50.0
30.0
10.0
L131 x L3-77
6.1
42.4
39-4
12.1
0K51 x L131
47.2
39 .6
9-4
3.8
W.S. x L21
40 .7
44.4
11.1
3-7
57.1
42.9
Parentage
L9-39 x NC171
5
5/16'
i nf l u e n c e was not
as the male.
i n d ic a t e d f o r the o th er parents when they were used
L3-77 di d not e x e r t t h i s
when i t was used as the female p a r e n t.
i n flu en c e on the c o r t e x th ickness
In g e n e r a l,
the data were skewed
somewhat toward the t h i n n e r or more d e s i r a b l e c o r t e x .
by s e l e c t i o n pressures e x e r t e d
This is e x p la i n e d
in the development of the pa re n ts .
i n d ic a t e s t h a t s e l e c t i o n f o r a t h i n c o r t e x is p r a c t i c a l .
should encounter l i t t l e
d iffic u lty
The breed er
in s e l e c t i n g f o r a t h i n c o r t e x .
The thickness o f the c o r t e x l a y e r o f sweet p o t a t o roots
portant fo r at
l e a s t two reasons.
This
is
im­
In handling the harvested roots a
c e r t a i n amount o f damage from brusing occurs.
Frequently,
t h i s damage
is e x h i b i t e d by sloughing o f f o f the c o r t e x and the deeper the c o r t e x
the g r e a t e r
layer
is the area of exposed t i s s u e .
is o f g r e a t e s t
importance t o the processing i n d u s t r y .
cessor, e s p e c i a l l y canners,
quently,
the c o l o r w i l l
shown in P l a t e 6.
color,
The depth o f the c o r t e x
The pr o ­
p r e f e r s a product of uniform c o l o r .
vary q u i t e markedly in the c o r t i c a l
When the c o r t e x is deep (or t h i c k )
the processor must remove a l l
a u n i f o r m l y colored product th er eby
o f the c o r t i c a l
Fre­
zone as
and o f a d i f f e r e n t
t is s u e s t o o b t a i n
i nc r ea si ng the waste and a f f e c t i n g
the economics o f the o p e r a t i o n .
The data presented i n d i c a t e t h a t c o r t e x thic kne ss
character.
of genes
is an i n h e r i t e d
I t behaved in a t y p i c a l l y t r a n s g r e s s i v e manner.
The number
involved is probably few w i t h a simple a d d i t i v e e f f e c t .
The c o r r e l a t i o n c o e f f i c i e n t between the shape
tex thick nes s
is presented
in Ta bl e 35.
was s i g n i f i c a n t but o f a low magnitude.
(L:W r a t i o ) and c o r ­
The ne g at iv e v a l u e ,
r = .138,
In ap pr ox im at el y 2 per cen t of
the p o p u l a t i o n , c o r t e x thic kne ss and r oo t shape were c o r r e l a t e d due to
h e r i t a b l e causes.
Smoothness and c o r t e x th ickness were not c o r r e l a t e d .
52
PLATE 6:
V a r i a t i o n in the Thickness and Color o f the Cortex
in Roots o f the Progeny of the Cross L3-93 x L l - 8 0
TABLE 11:
Frequency D i s t r i b u t i o n of Number of Sweet Potato Seedlings
of Each Progeny into D i f f e r e n t Classes Based on Dry M at te r
Content
Per Cent Dry Matt er
Progeny
Mean
Standard
Error
24.92
2.11
9
28.52
2. 02
2
1
24.25
1.49
3
3
4
29.91
2. 93
13
24
31
16
31. 28
0. 83
5
5
2
3
2
28.84
1.27
12
28. 48
0.84
25. 84
0.86
Be 1ow
20
20-23
23-26
L3-80 x L3-77
2
3
2
L3-77 (X)
5
15
21
L3-77 x NCI71
5
4
Parentaqe
29-32
32-35
1
2
32
29
16
5
2
2
2
4
2
10
2
L3-80 (X)
Kandee (X)
1
L3-77t x L131
26-29
Over
35
L3-77 x L l - 8 0
2
10
29
38
24
20
L3-77 x K
4
6
13
9
4
5
L3-77 x L3-80
4
14
33
24
28
17
16
29.07
0.58
L3-80 x K
1
3
9
7
1
2
4
27-36
1.16
K x L3-77
1
1
4
3
1
2
26.88
1-7*1
K x L3-80
2
1
2
4
1
24.45
2. 10
•
Cont i nued
TABLE 11:
Cont i nued
!
Per Cent Dry M at t e r
Be 1ow
20
L3-93 x L131
Pa rentaqe
26-29
29-32
32-35
13
9
5
5
14
22
21
9
10
8
8
7
1
5
2
2
20-23
23-26
9
10
L3-93 x L l - 80
5
L8-3 x L l-8 0
7
Ll-171 x L131
Progeny
Mean
Standard
Err or
7
26.42
0.88
9
27.69
0.65
4
25.11
1.13
25.41
1.28
Over
35
1
L131 x L3-77
3
6
6
8
4
4
3
27.09
1.26
0K51 x L131
3
6
8
12
9
8
7
27.72
1.88
W.S. x L21
1
2
2
4
9
5
4
29.85
1.24
L9-39 x NC171
1
3
1
2
23.44
2.06
L3 -7 7t x L131
5
3
3
6
26.74
1.47
2
3
2
1
\n
Sr
TABLE 12:
Parentage
L3-80 x L3-77
L3-77 (X)
L3-77 x NC171
Percentage of Sweet Potato Seedlings of Each Progeny
in D i f f e r e n t Classes Based on Dry Matt er Content
2
20-23
3
23-26
20.0
30 .0
20.0
3-9
11.8
16.5
23 .8
19.0
Class
1
Per Cent Dry M at te r 0-20
5
29-32
6
32-35
10.0
20.0
25.2
22.8
12.6
7-1
23 .8
9.5
9.5
9.5
4.8
12.5
25.0
18.8
18.8
25-0
2.1
10.3
13.4
24.7
32.0
16.5
10.5
26.3
26.3
10.5
15.8
10.5
8.8
L3-80 (X)
Kandee (X)
1.0
7
35-Up
1.5
7.4
21.3
27 .9
17.6
14.7
L3-77 x K
9.8
14.6
31.7
21 .9
9.8
12.2
L3-77 x L3-80
2.9
10.1
23.9
17.4
20.3
12.3
11.6
L3-80 x K
3.7
11.1
33-3
25 .9
3.7
7. 4
14.8
K x L3-77
33.3
25.0
8.3
16.7
*
Va J
L3-77 x L l - 8 0
CO
L3-77t x L131
4
26-29
8.3
K x L3-80
20.0
10.0
20.0
40.0
10.0
L3-93 x L131
15.5
17.2
22. A
15-5
8.6
Cont i nued
8.6
12.1
I
Parentage
L3-93 x L l-8 0
L8-3 x L l-8 0
Cl ass
Per Cent Dry Matter
TABLE 12:
C o n tin u e d
2
20-23
3
23-26
k
26-29
5
29-32
6
32-35
7
35-Up
5.6
15-6
24. 4
23.3
10.0
11.1
10.0
20.0
22 .9
22 .9
20.0
2.9
50.0
20.0
20.0
1
0-20
LI -171 X LI 31
11.4
10.0
L I 31 X L3-77
9-1
18.2
18.2
24.2
12.1
12.1
9.1
0K51 x LI 3 1
5.6
11.1
14.8
22.2
16.7
14.8
33.0
W.S. x L21
3.7
7- 4
7.4
14.8
33.3
18.5
14.8
L9-39 x NCI71
14.3
42.9
14.3
28.6
L3- 77t x L I 31
20. 8
12.5
12.5
25.0
8.3
12.5
8.3
V J1
ON
57
Inher i tance o f Dry M a t t e r
The data presented in Table
11 gives the frequency d i s t r i b u t i o n
o f the number o f see dling s of each progeny i n to d i f f e r e n t classes based
on the dry m at te r c o n te n t.
12.
The data in percentages ar e given
in Table
In each progeny t her e were see dling s w i t h a dry m at ter co n te n t a-
bove the hi ghe st pa re nt and below the lowest p a r e n t.
These dat e
indi­
ca t e t h a t t ra n s g r e s s i v e segre gat ion did occur as po in te d out by Hernan­
dez (49) and Con st ant in
(24).
The data d i f f e r e d somewhat from those of
Hernandez in t h a t he found the progeny mean in most cases was a p p r o x i ­
mately equal
to the mean o f the two p ar en ts .
agree w i t h those of Constantin
the mean o f the p a r e n ts .
in t h a t the progeny means were lower than
This was p a r t i c u l a r l y t r u e when the parents
were both r e l a t i v e l y high in dry m a t t e r .
the o t h e r
These r e s u l t s more ne a rl y
When one paren t was high and
low, the progeny mean more n e a r l y approached the mean o f the
parents.
The c o r r e l a t i o n c o e f f i c i e n t s e x h i b i t e d
in Table 35 showed no s i g ­
n i f i c a n t c o r r e l a t i o n between number of roots of each see dling and dry
m a t te r c o n t e n t ,
smoothness and dry m a t t e r ,
and c o r t e x thickness and dry
m atter.
Dry m a t te r con ten t was a q u a n t i t a t i v e c h a r a c t e r c o n t r o l l e d by se­
ve r a l
genes s eg re ga tin g in a t r a n s g r e s s i v e manner.
lacked dominance and were a d d i t i v e
The genes a p p a r e n t ly
in e f f e c t .
Inheri tance o f Carotene
Frequency d i s t r i b u t i o n o f the number o f see dlings of each progeny
i n t o each carotene
(total
pigments) cl ass
percentage o f the see dl in gs
two o f the p ar en ta l
in each class
is shown in Table 13 and the
is shown in Table 14.
Only
l i n e s were very low in carotene content and they
TABLE 13:
Parentaqe
Class
3
mg/100 gm
fresh wt. 0-1
Frequency D i s t r i b u t i o n of Number of Sweet Potato Seedlings
o f Each Progeny into Classes Based on Carotene Content
of the Roots
2
3
k
5
6
7
8
9
1-3
3-6
6 -9
9-12
12-15
15-18
18-21
21 +
Progeny
Mean
Standard
Error
3
k
13.40
.574
21
2k
7
10
lk
15
26
43
2k
12.54
L3-77 x NC171
2
3
7
3
7
3
9
3
3
11.16
• 533
L3-80 (X)
7
1
2
2
2
1
1
6.21
.625
4.98
.021
L3-77 (X)
v jD
1
00
2
L3-80 x L3-77
37
18
16
5
6
5
6
k
L3-77t x L131
2
3
2
2
k
2
4
k
1
12.06
.568
L3-77 x L l - 8 0
7
5
7
9
\k
11
16
29
38
15.71
.404
L3-77 x K
5
5
4
6
9
k
3
9.6 4
.396
L3-77 x L3-80
5
18
16
15
15
\k
L3-80 x K
1
2
6
3
1
K x L3-77
2
k
1
K x L3-80
2
1
1
Kandee (X)
1
1
4
1
23
22
9
10.89
.024
5
6
3
12.41
.562
2
2
8.65
.896
2
2
10.51
1.027
Cont i nued
1
TABLE 13:
Parentaqe
Class
mg/100 gm
f re sh wt.
1
0-1
L3-93 x L131
2
3
4
5
C o ntin u e d
6
7
8
12-15
15-18
18-21
9
21 +
Progeny
Mean
Standard
Er ror
1-3
3-6
6-9
9-12
3
5
9
9
7
11
10
3
12.76
.030
L3-93 x L l - 8 0
1
9
7
11
10
8
13
17
lif
15.20
.029
L8-3 x L l -8 0
1
1
2
2
3
2
10
5
9
17.01
. if l9
1
2
1
2
2
1
1
l i t . 92
.730
1
if
1
2
3
6
9
12.22
.565
1
2
3
if
2
12. lit
.568
2
lif
6
1 1.60
1.090
3. 18
1.060
Ll-171 x L I 31
L131 x L3-77
2
L3-77 x L131
5
3
0K51 x L131
2
3
6
9
8
W.S. x L21
9
7
5
if
1
L21 x W.S-
18
3
2
1
1
L9-39 x NC171
1
2
1
2
3
1
2.97
. 03if
2
2
10.80
.899
TABLE 14:
Percentage of Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Classes Based on Carotene Content of the Roots
1
2
3
4
5
6
7
8
9
0-1
1-3
3-6
6-9
9-12
12-15
15-18
18-21
21-Up
20.0
10.0
30.0
40.0
1 1 .4
13.0
3.8
5.4
7.6
8. 2
14.1
23 .4
13.0
5.0
7.5
17.5
7.5
17.5
7.5
22.5
7.5
7. 5
L3-80 (X)
43.8
6. 3
12.5
12.5
12.5
6. 3
6.3
Kandee (X)
37 .8
18.4
16.3
5.1
6.1
5.1
6.1
4.1
L3-77t x L I 31
8.3
12.5
8. 3
8.3
16.7
8.3
16.7
16.7
4.2
L3-77 x L l-8 0
5.1
3.7
5.1
6.6
10.3
8.1
11.9
21.6
27.9
12.2
12.2
9.8
14.6
21 .9
9.8
7. 3
!
9.8
2.4
L3-77 x L3-80
3.6
13.0
11.6
10.9
10.9
10.1
16.7
15.9
6. 5
L3-80 x K,
3.7
7.4
22.2
11.1
3. 7
18.5
22.2
11.1
K x L3-77
16.7
33.3
8. 3
16.7
16.7
K x L3-80
20.0
10.0
10.0
10.0
20.0
20.0
10.0
12.1
18.9
17-2
5.2
Parentaqe
L3-80
X
L3-77
L3-77 (X)
L3-77 x NCI71
L3-77 x K
L3-93 x L ^ l
Cl ass
mg/100 gm
fresh w t .
5.2
8.6
15.5
8.3
15.5
Cont i nued
TABLE 14;
Class
1
mg/100 gm
Pa rentage______ f re sh wt.______O^J
Cont i nued
4
5
6
7
8
9
1- 3 ______ 3-6
6 -9
9-12
12-15
15-18
18-21
21-Up
2
3
13-93 x L l - 8 0
1.1
10.0
7.8
12.2
11.1
8.9
14.4
18.9
15.6
L8-3 x L l - 8 0
2.9
2.9
5. 7
5.7
8.6
5. 7
28.6
14.3
25 .7
10.0
20.0
10.0
20.0
20.0
10.0
10.0
3. 0
12.1
3. 0
6.1
9.1
18.2
27.3
6.7
13.3
20.0
26.7
13.3
17.3
15.4
3.8
26.9
11.5
Li-171 x L I 31
L I 31 X L3-77
6.1
20.0
L3-77 x LI 31
0K51 x L131
15.2
3.8
5. 8
11.5
f
W.S. x L21
33.3
25 .9
18.5
14.8
3.7
L21 x W.S.
62.1
10.3
6.9
3.4
3.4
L9-39 x NCI71
14.3
28.6
3. 7
;
10.3
3-4
28. 6
28.6
3.8
PLATE 7:
V a r i a t i o n in the I n t e r n a l Color of the Roots
in the Progeny of the Cross L3-93 x L l - 8 0
63
were used only in combination w it h each o t h e r .
st udi ed were derived by s e l f i n g each p a r e n t.
Three of the progenies
In each case the mean
carotene content of the progeny was a p p re ci a bl e
mean.
lower than the parental
The mean carotene content of the cross W h i t e s t a r x L21 was higher
than the mean of the parents but s t i l l
crosses, the progeny mean f e l l
very low.
In many o f the other
between the two parents - u s u a l l y c l o s e l y
approaching the mean of the two par en ts.
of Hernandez (49) and Constantin
This study,
u n l ik e the work
(24) did not include crosses between
parents in which one was high and the o t h e r low in carotene, but s i m i ­
l a r i t i e s were e v i d e n t .
Carotene content was a q u a n t i t a t i v e c h a r a c t e r ,
t h a t segregated in a tra n s g r e s s iv e manner.
When the data were studied
t o g e t h e r they supported the conclusion of Hernandez (49)
genes, probably 6, c o n t r o l l e d carotene c o n te n t.
nance was suggested.
The genes were a d d i t i v e
t h a t several
The absence o f domi­
in e f f e c t and the po s s ib i ­
l i t y o f some e p i s t a t i c gene e f f e c t s were i n d ic a t e d .
The c o r r e l a t i o n c o e f f i c i e n t s presented in Table 35 show t h a t caro­
tene was not c o r r e l a t e d w i t h the number o f roots per p l a n t ,
of the r o o t s , or thickness o f the c o r t e x .
correlation
matter.
smoothness
A h i g h l y s i g n i f i c a n t negative
( r = - . 569) was obtained between carotene content and dry
I f s e l e c t i o n s were based on high carotene content al one ,
approximately one t h i r d of the seedlings would be low in dry m a t t e r .
h i g h l y s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n was obtained between carotene
and moistness
(r = + .6 0 1 ),
between carotene and firmness
and between carotene and f l a v o r
(r - +.217).
(r = +.5 1 4 ),
In view of the negative
c o r r e l a t i o n between carotene and dry m a t t e r , a p o s i t i v e r e l a t i o n s h i p
would be expected between carotene and moistness, and t h i s r e l a t i o n ­
ship is shown.
The carotene and f l a v o r c o r r e l a t i o n suggests t h a t
A
64
f l a v o r r a t in g s were influenced by c o l o r .
The c o r r e l a t i o n between carotene and firmness ( r = + .5 14 ) a c t u a l l y
showed t h a t as carotene values increased, firmness decreased because
firmness r a t in g s were scaled from 1 through 5 w it h 5 being le a s t f i r m .
Several workers
(12, 40, 92) have attempted t o r e l a t e firmness to pec-
t i c substances and have suggested t h a t s p e c i f i c enzyme systems are i n ­
volved.,
I f a s p e c i f i c enzyme system is res po ns ib le , ap p ar en tly
it
is
l in k e d w i t h carotene synthesis and is g e n e t i c a l l y c o n t r o l l e d .
In her i tance of Skin Color
The frequency d i s t r i b u t i o n o f the sweet potat o seedlings o f each
progeny i n t o d i f f e r e n t skin co lo r classes
the percentage o f the seedlings
None o f the pare nt al
progeny.
in each class
is shown in Table 16.
P l a t e 8 shows the v a r i a t i o n
The q u a n t i t a t i v e nature of
is shown by the data.
in Table 15 and
li n e s had purpl e skin c o l o r and only one was c l a s s ­
ed as cream (Table 1) .
typical
is presented
In g e n e r a l,
in skin co lo r o f a
i n h e r i ta n c e f o r skin c o l o r
the darker the skin c o l o r of the pa­
rents the g r e a t e r was the percentage of seedlings with darker skin
color.
Transgressive segregation occurred,
since in a l l
crosses t her e
were seedlings w it h l i g h t e r and some w ith da r ke r skin c o l o r than e i t h e r
parent.
When the female parent had a darker skin than the male, the
g r e a t e r p a r t o f the progeny had a dark skin c o l o r .
I f the female pa­
r e n t had a l i g h t e r skin c o l o r than the male, the g r e a t e r p a r t of the
progeny had a l i g h t skin c o l o r .
This suggests a strong influence of
the female parent on the skin c o l o r .
Hernandez (49) and Constantin (24)
in d ic a t e d skin c o l o r was con­
t r o l l e d by several genes t h a t were complementary.
suggested a basic gene f o r c o l o r
Hernandez f u r t h e r
(D) and the presence o f complementary
TABLE 15:
Frequency D i s t r i b u t i o n of Number of Sweet Potato Seedlings of
Each Progeny into D i f f e r e n t Skin Color Classes
Parentage
Cream
Tan
Copper
Rose
Purple
L3-77 (X)
9
61
63
25
26
Kandee (X)
16
19
38
13
12
L3-80 (X)
3
2
5
4
2
L3-77 x Kandee
6
14
6
8
7
L3-77 x L3-80
14
41
53
15
15
Kandee x L3-77
3
1
4
4
Kandee x L3-80
2
2
L3-80 x L3-77
L3-80 x Kandee
4
L3-77 x L131
3
3
1
4
2
3
4
11
4
4
15
14
6
4
L131 x L3-77
4
9
13
7
L3-77 x NC171
1
8
14
12
5
L3-77 x L l-8 0
4
44
49
19
20
L3-93 x L131
12
20
18
6
2
Conti nued
TABLE 15:
Parentage
Cream
C o n tin u e d
Tan
Copper
Rose
Purple
L3-93 x L I -80
9
22
38
15
6
L8-3 x L I -80
3
10
8
8
6
0K51 x L I 31
5
14
26
4
4
LI -171 X LI 31
2
2
3
2
1
W.S. x L21
22
2
L2I x W.S.
22
4
1
1
i
1
1
3
2
L9-39 x NCI71
3
TABLE 16:
P ercentage o f Sweet P o ta to S e e d lin g s o f Each
Progeny In D i f f e r e n t S k in C o lo r Classes
Parentage
Cream
L3-77 (X)
4.9
Kandee (X)
Tan
Copper
Rose
Purpli
33.2
34.2
13.6
14.1
16.3
19.4
38 . 8
13.3
12.2
L3-80 (X)
18.8
12.5
31.2
25.0
12.5
L3-77 x K
14.6
34.1
14.6
19.5
17.1
L3-77 x L3-80
10.1
29-7
38.4
10.9
10.9
K x L3-77
25.0
8.3
33.3
33.3
K x L3-80
20.0
20.0
30.0
30.0
10.0
40 .0
20.0
30.0
14.8
40.7
14.8
14.8
38.5
35.9
15.4
10.3
12.1
27.3
39. 4
21.2
L3-77 x NC17I
2.5
20.0
35.0
30 .0
12.5
L3-77 x L I -8 0
2. 9
32. 4
36 .0
13.9
14.7
L3-80 x L3-77
L3-80 x K
14.8
L3-77 x L131
L I 31 x L3-77
Cont i nued
TABLE 16:
C o ntinue d
Cream
Tan
Copper
Rose
Purple
L3-93 x L131
20.7
34.5
31.6
10.3
3.4
L3-93 x L I -80
10.0
24.4
42.2
16.7
6.7
L8-3 x L l - 8 0
8.6
28. 6
22. 9
22.9
17.1
0K51 x L131
9.3
25.9
48.1
7.4
7. 4
Ll-171 x L131
20.0
20.0
30.0
20.0
10.0
W.S. x L21
81.5
7.4
L21 x W.S.
75 . 9
13.8
3.4
3. 4
3.4
14.3
14.3
42.9
28. 6
Parentage
L9-39 x NC171
11.1
69
PLATE 8:
Skin Color V a r i a t i o n o f Roots of D i f f e r e n t Seedlings
in the Progeny o f the Cross L3-77 x L3-80
70
genes
(C and R ) .
Constantin s t a t e d t h a t purple appeared to be p a r t i a l l y
dominant.
These data
i n d ic a t e several genes ar e
involved and are a d d i t i v e
in
e f f e c t , with an absence of dominance, and the p o s s ib le presence of an
i n h i b i t o r t h a t may be cytop las mic .
I n h e r i ta n c e of Characters C o n t r i b u t i n g t o Bakinq Q u a l i t v
The seedlings of each progeny were al s o rated f o r c e r t a i n q u a l i t i e s
of th e baked f l e s h .
The important q u a l i t y ch ar ac te rs c o n t r i b u t i n g to
the baking index were c o l o r , moistness,
fib e r.
Color was div id ed
sweetness, f l a v o r , f irm nes s and
i n t o two p a r t s -
i n t e n s i t y and u n i f o r m i t y .
F i b e r , which was the only o b j e c t i v e measurement o f the baked roots was
d i v i d e d as percentage f i b e r and f i b e r s i z e .
mined by a n a l y t i c a l
Percentage f i b e r was d e t e r ­
procedures and f i b e r siz e was a vi su al c l a s s i f i c a ­
t i o n o f the f i b e r s based on di am et er .
I n h e r i t a n c e of Co lo r I n t e n s i t v
Frequency d i s t r i b u t i o n o f number o f sweet p o t a t o seedlings o f each
progeny in to c o l o r
i n t e n s i t y classes
centage in each cl ass
is shown in Tab le 17 and the pe r­
is shown in Table 18.
The1 c o l o r i n t e n s i t y of the
baked roots was c l o s e l y c o r r e l a t e d w i t h the carotene content o f the raw
roots as shown by the r value
(+.9^0
in Table 35.
s i m i l a r to t h a t shown f o r carotene content
l in g s
The data a r e very
in the raw roots o f the seed­
in Table 13-
Inher i tance of Color U n I f o r m i t y
D i s t r i b u t i o n o f the see dling s o f each progeny i n t o d i f f e r e n t
cl asses based on the u n i f o r m i t y o f the c o l o r in the baked roots
is shown
TABLE 17:
1
2
L3-80 x L3-77
2
1
L3-77 (X)
1
4
L3-77 x NCI71
2
1
L3-80 (X)
5
L3- 77t x NC171
5
Parentage
Class*
Frequency D i s t r i b u t i o n of Number of Sweet Potato Seedlings
o f Each Progeny i n to D i f f e r e n t Classes Based on Color
I n t e n s i t y of the Baked Roots
3
4
3
2
Progeny
Mean
Standard
Error
5.0
0. 90
4.5
0.49
4.9
0.38
1
3.2
0.56
2
3.5
0.48
1.6
0.21
4.2
0. 45
5
6
7
8
2
1
1
3
6
3
1
1
8
6
1
I
1
9
1
10
1
5
1
3
2
16
5
4
4
L3-77t x L131
5
1
3
2
4
5
4
L3-77 x L I -80
2
5
4
8
10
10
21
14
5.6
0.23
L3-77 x K
8
3
3
6
13
3
4
1
3.9
0. 32
23
22
12
19
27
19
31
17
4
4.7
0.18
L3-80 x K
1
3
3
4
1
1
7
4
3
5.6
0.48
K x L3-77
5
1
3
1
2
2. 3
0.45
Kandee (X)
L3-77 x L3-80
5
Continued
TABLE 17:
C o n tin u e d
Progeny
Mean
Standard
Error
3.6
0. 62
1
5-0
0.25
11
6
5.2
0.24
11
8
1
6. 2
0. 32
1
2
2
2
5. 7
0.11
6
3
5.4
0.4 5
2
1
4.9
0. 27
2.1
0.3 3
4.0
0.62
1
2
3
4
5
K x L3-80
2
1
1
2
3
L3-93 x LI31
1
6
6
7
17
7
7
5
L3-93 x L I -80
7
5
9
10
19
9
14
1
1
2
2
6
3
2
Parentaqe
C la ss *
0
1
00
X
_i
1
C*\
CO
1
LI -171 x LI 31
6
7
4
2
3
2
6
1
6
0K51 x L I 31
3
5
4
6
14
9
8
13
7
1
3
2
1
2
2
L9-39 x NC171
*
1
Color was rated on a numerical
orange (or i d e a l ) .
9
1
L131 x L3-77
W.S. x L21
8
,
1
I
10
scale fro m I to 10 where 1 = White (or very l i g h t )
and 10 = Deep
TABLE 18:
Parentage
C la ss *
1
Percentage of Sweet Potato Seedlings of Each Progeny in
D i f f e r e n t Classes Based on Color I n t e n s i t y of Baked Roots
2
20 .0
10.0
L3-77 (X)
5.0
20.0
L3-77 x NC171
9. 5
4.8
L3-80 x L3-77
L3-80 (X)
38.5
L3-77t x NC171
27.8
Kandee (X)
3
4
15.0
9.5
5
6
8
7
20.0
10.0
10.0
30.0
30 .0
15.0
5.0
5.0
38.1
28.6
4.8
A. 8
7. 7
7.7
9
5.0
7. 7
38.5
5.6
16.7
11.1
55.2
17.2
13.8
13.8
L3 -7 7t x L131
20.8
4.2
12.5
8. 3
16.7
20.8
16.7
L3-77 x L I -80
2.7
6.8
5.4
10.8
13.5
13.5
28.4
18.9
L3-77 x K
19.5
7.3
7.3
14.6
31 .7
7.3
9.8
2.4
L3-77 x L3-80
13.2
12.6
6.9
10.9
15.5
10.9
17.8
9.8
2. 3
L3-80 x K
3.7
11.1
11.1
14.8
3.7
3.7
25.9
14.8
11.1
K x L3-77
41.7
8.3
25 .0
8.3
16.7
K x L3-80
20.0
10.0
10.0
20 .0
30.0
11.1
27.8
10.0
Cont i nued
10
TABLE 18:
Parentage
Class*
1
2
3
4
C o ntin u e d
5
6
7
8
9
L3-93 x L131
1.8
10.5
10.5
12.3
29.8
12.3
12.3
8.8
1.8
L3-93 x L I -80
7.8
5-6
10.0
11.1
21.1
10.0
15.6
32.2
6. 7
L8-3 x L I -80
2.9
2.9
5.7
5.7
17.1
8. 6
31 .4
22 .9
2. 9
20 .0
10.0
20.0
20.0
20.0
10.0
Ll-171 x L131
12.1
6.1
9.1
6.1
18.2
3.0
18.2
18.2
9.1
5.8
9.6
7-8
11.5
26.9
17.3
15.4
3.8
1.9
W.S. x L21
48.1
25 .9
3. 7
11.1
7.4
L9-39 x NCI71
14.3
14.3
28 .6
28.6
L131 x L3-77
0K51 x L I 31
*
3.7
14.3
Color was rated on a numerical scale from 1 to 10 where 1 = White
orange (or i d e a l ) .
(or very l i g h t )
and 10 = Deep
10
TABLE 19:
Parentaqe
Cl ass* 1
2
Frequency D i s t r i b u t i o n o f Number o f Sweet P o ta to S e e d lin g s
Each Progeny i n t o D i f f e r e n t Classes Based on U n i f o r m i t y o f
C o lo r o f th e Baked Roots
3
4
5
1
L3-80 x L3-77
6
7
8
9
2
2
4
1
30
in
Progeny
Mean
Standard
Error
6.9
0. 62
L3-77 (X)
2
3
2
8
5
6.6
0.29
L3-77 x NC171
1
3
8
3
6
6. 5
0.26
L3-80 (X)
2
4
2
4
1
6.7
0.43
6
6
3
1
2
6.3
0.31
2
3
4
6
5
7
6.8
0.35
4
2
6
5
5
2
6. 5
0. 32
L3 -7 7t x NC171
2
Kandee (X)
L3 -7 7t x L131
L3-77 x L l -80
1
4
2
7
9
14
1
6.7
0.24
L3-77 x K
1
3
5
9
10
10
3
6.9
0.23
4
11
21
26
42
30
2
6.3
0. 12
3
5
3
2
13
1
6. 7
0.30
1
2
2
3
1
2
6.3
0.59
1
1
3
2
2
6.8
0. 66
1
L3-77 x L3-80
L3-80 x K
1
K x L3-77
K x L3-80
1
Cont i nued
TABLE 19:
C o ntinue d
Progeny
Mean
Standard
E rr or
2
e .b
0.21
9
6.7
0 .15
6
6. 3
0 .19
3
3
6. 5
0.A5
5
16
6
1
6.8
0 .1 9
15
9
lit
9
1
6.2
0 .19
W.S. x L21
6
5
5
8
3
6.9
0.26
L9-39 x NCI71
1
1
2
3
7.0
0.it4
2
3
b
5
6
7
8
9
2
2
2
9
8
19
13
3
2
13
18
2b
21
L8-3 x L I -80
2
6
9
12
L1—171 x L131
I
2
1
L131 X L3-77
1
b
2
Parentaqe
L3-93 x L I 31
L3-93 x L I -80
0K51 x L I 31
*
Class* 1
2
10
Color u n i f o r m i t y was rated on a numerical scale from 1 to 10 where 10 = E x c e l le n t u n i f o r m i t y of
c o lo r and 1 - Extremely poor u n i f o r m i t y of colors
TABLE 20:
Parentage
Cl ass* 1
2
Percentage o f Sweet P o ta to S e e d lin g s in Each Progeny in
D i f f e r e n t Classes Based on U n i f o r m i t y o f C o lo r o f the
Baked Roots
4
3
5
10.0
L3-80 x L3-77
*
L3-77 (X)
L3-77 x NCI71
L3-80 (X)
9
20.0
20.0
40 .0
10.0
10.0
40.0
25.0
4.8
14.3
38.1
14.3
28 .6
30 .8
15.4
30 .8
7-7
33.3
33.3
16.7
5.6
11.1
6.9
10.3
13.8
20.7
17.2
24.1
16.7
8.3
25-0
20 .8
20.8
8.3
L3-77 x L I -80
2. 6
10.5
5.3
18.4
23.7
36.8
2.6
L3-77 x K
2.4
7. 3
12.9
21 .9
24 .4
24 .4
7.3
2.9
8.0
15.3
19.0
30.7
21 .9
1.5
11.1
18.5
11. 1
7.4
48.1
3. 7
8.3
16.7
16.7
25.0
•00
L3-77t x L131
8
15.0
L3-77t x NCI71
6.9
7
10.0
15-4
Kandee (X)
6
16.7
10.0
10.0
30.0
20.0
20.0
L3-77 x L3-80
0.7
L3-80 x K
K x L3-77
K x L3-80
8. 3
10.0
C o ntinued
"J
TABLE 20:
C o n tin u e d
2
3
4
7
8
3. 5
3.5
3. 5
15.8
14.0
33.3
22 .8
3. 5
3.3
2.2
14.4
20.0
26.7
23-3
10.0
L8-3 x L1—80
5.7
17.1
25 .7
34.3
17.1
L1-171 x L I 31
10.0
20 .0
10.0
30.0
30.0
3.0
12.1
15.2
48 .5
18.2
3.0
3.8
28.8
17.3
26.9
17.3
1.9
W.S. x L21
22.2
18.5
18.5
29.6
11.1
L9-39 x NCI71
14.3
14.3
28.6
42.9
Parentage
Cl ass * 1
L3-93 x L I 31
L3-93 x L I -80
L I 31 x L3-77
0K51 x L I 31
3.8
5
6
9
Color u n i f o r m i t y was rated on a numerical scale from 1 to 10 where 10 = E x c e l l e n t u n i f o r m i t y of
c o l o r and 1 = Extremely poor u n i f o r m i t y o f c o l o r .
10
79
in Table 19 and the percentage o f seedlings in each class
' i n Table 20.
A ll o f the pa re n ta l m a t e r ia l
is presented
had been subjected to s e l e c ­
t i o n pressures in the past thus extremes in u n i f o r m i t y were not r e ­
presented.
As shown by the progeny means in Table 19, d i f f e r e n c e s be­
tween any two progenies were not pr es e nt .
W it h in i n d i v i d u a l progenies
d i s t r i b u t i o n was very uniform over a r a t h e r narrow range.
were skewed toward the r i g h t , o r toward g r e a t e r u n i f o r m i t y ,
ed to f i t
a normal d i s t r i b u t i o n curve.
o f co lo r is c o n t r o l l e d by several
This
The data
but appear­
i n d ic at es t h a t u n i f o r m i t y
genes t h a t are a d d i t i v e in e f f e c t and
segregate t r a n s g r e s s i v e l y .
Inher i tance o f Moi stness
Frequency d i s t r i b u t i o n o f the number o f sweet potat o seedlings o f
each progeny into d i f f e r e n t moistness classes is presented in Table 21
and the percentage o f each pop ulatio n in each class is given in Table
22.
The progeny means ranged from 4 . 6 to 7-1 and any given mean us u al ly
fe ll
between t h a t o f each o f the two p ar en ts .
used as the male,
the progeny mean c l o s e l y approached i t .
the high paren t was used as the female,
a mid -p o in t between the two p a r e n ts .
duals we ll
When the high parent was
above and other s well
However,
if
the mean o f the progeny f e l l
at
In each progeny there were i n d i v i ­
below the mean o f e i t h e r p a r e n t.
This
in d ic a t e s t h a t moistness is a q u a n t i t a t i v e ch a ra ct er c o n t r o l l e d by se­
vera l
genes segregating t r a n s g r e s s 5v e l y .
Dominance was not ev i d e n t,
and the e f f e c t o f the genes appeared to be a d d i t i v e .
As shown by the r values in Table 35, moistness was r a t h e r c lo s e l y
r e l a t e d to several
ness and f l a v o r
factors.
( r = + .4 01 )
Carotene and moistness
(r = + . 6 0 1 ) , mo is t­
and moistness and firmness
(r = +.6 92 ) were
TABLE 21;
Parentaqe
Class * 1
2
Frequency D i s t r i b u t i o n o f Number o f Sweet P o ta to S e e d lin g s
o f Each Progeny i n t o D i f f e r e n t C lasses Based on M o is tn e s s
o f th e Baked Roots
3
4
5
6
2
L3-80 x L3-77
L3-77 (X)
1
L3-77 x NCI71
3
L3-80 (X)
2
L 3- 77 t x NCI 71
Progeny
Mean
Standard
E rror
1
7.1
1.97
7
8
9
2
5
10
1
2
2
5
3
3
6.2
0.49
3
5
2
4
2
2
5.6
0.47
2
2
3
3
1
4.8
0.56
1
5
4
2
4
1
1
5.0
0.50
Kandee (X)
1
2
3
5
6
8
2
2
5.9
0.32
L3 -7 7t x L131
1
3
3
2
4
6
5
6.8
0.40
L3-77 x L I -80
2
L3-77 x K
L3-77 x L3-80
L3-80 x K
4
3
1
1
1
16
18
24
8
3
6.6
0.18
2
1
2
7
5
13
6
5
6.4
0.28
14
10
19
21
30
44
29
3
5.8
0.15
3
1
2
2
3
6
9
1
6.2
0.41
3
3
1
3
6.8
0.51
1
2
2
1
6. 3
0. 56
K x L3-77
2
K x L3-80
2
2
Cont i nued
TABLE 21:
Class * 1
2
L3-93 x L131
1
L3-93 x L1-80
2
Parentaqe
L8-3 x L I -80
2
4
1
5
4
1
Progeny
Mean
Standard
Error
5
6.5
0.26
17
7
6. 3
0. 20
9
9
2
6. 2
0.33
1
7
1
6.5
0.33
9
6
3
3
2
4
4
3
7
8
9
9
14
16
15
11
28
b
3
1
L1-171 x L131
C o ntinue d
10
L131 x L3-77
1
1
3
1
2
6
6
10
3
6.4
0. 37
0K51 x L I 31
1
2
2
2
2
5
10
16
12
7.0
0.28
W.S. x L21
1
2
4
5
7
3
5
4.6
0.33
1
1
7.1
0.63
L9-39 x NCI71
1
*
scale from 1 to 10 where 1 = Very dry and 10 = Very moist.
Moistness was rated on a numerical
3
1
TABLE 22:
Parentage
Percentage o f Sweet P o ta to S e e d lin g s o f Each Progeny In
D i f f e r e n t Classes Based on M o is tn e s s o f th e Baked Roots
2
Cl ass* I
3
4
5
6
7
8
20.0
50.0
10.0
9
' I
20.0
L3-80 x L3-77
5.0
L3-77 (X)
15.0
5.0
10.0
10.0
25.0
15.0
15.0
14.3
23 .8
9. 5
19.0
9-5
9. 5
23.1
23.1
7.7
11.1
22.2
5.6
5. 6
14.3
L3-80 (X)
15.4
15.4
15.4
L3-77t x NCI7 1
5. 6
27.8
22 .2
Kandee (X)
3.4
6.9
10.3
17.2
20.7
27.6
6.9
6.9
L3-77t x L131
4.2
12.5
12.5
8.3
16.7
25 .0
20.8
2. 7
L3-77 x K
L3-77 x L3-80
L3-80 x K
2.3
1.4
1.4
1.4
21 .6
24.3
32.4
10.8
4.1
4.9
2.4
4.9
17.1
12.2
31.7
14.6
12.2
8.0
5.7
10.9
12.1
17.2
25.3
16.7
1.7
11.1
3. 7
7.4
7.4
11.1
22.2
33.3
3. 7
25 .0
25.0
25.0
10.0
20.0
20.0
10.0
K x L3-77
16.7
K x L3-80
20.0
20.0
Continued
•
L3-77 x L I -80
00
L3-77 x NCI71
5
TABLE 22:
Parentage
Cl ass* 1
C o ntinue d
2
3
4
5
6
7
8
9
10
8.8
L3-93 >< LI 31
1.8
1.8
8.8
5.3
5.3
15.8
15.8
24.6
28.1
L3-93 >< L I -80
2. 2
A.A
2.2
4.4
16.7
12.2
31.1
18.9
7.8
2.9
11.4
8. 6
11.4
8.6
25.7
25-7
5-7
10.0
70.0
10.0
L8-3 x L I -80
10.0
LI -171 x L I 31
LI 31 X L3-77
3. 0
3.0
9.1
3.0
6.1
18.2
18.2
30.3
9.1
0K5I x L131
1.9
3.8
3.8
3. 8
3.8
9.6
19.2
30.8
23.1
W.S. x L21
3.7
7.4
14.8
18.5
25 .9
11.1
18.5
14.2
14.2
42.9
14.2
L9-39 >< NCI71
*
14.2
Moistness was rated on a numerical scale from 1 to 10 where 1 = Very dry and 10 = Very moist.
CD
84
p o s i t i v e l y c o r r e l a t e d , w h il e dry m at te r and moistness (r = - . 5 7 2 ) were
negatively correlated.
ship was n e g a t i v e .
In r e a l i t y ,
the moistness and firmness r e l a t i o n ­
As the firmness score increased from 1 to 5 the p r o ­
duct became less f i r m ,
thus i f a baked root r a t e d high in moistness,
also r at ed high in f ir m n e s s ,
i n d i c a t i v e of a s o f t ro ot .
it
The negative
a s s o c i a t i o n between dry matter and moistness ( r = - . 5 7 2 ) was as one
would ex pe ct ; fo r example, the lower the dry m a t t e r ,
moistness and the hi gh er the moistness score,
root.
The moistness and f l a v o r a s s o c i a t i o n
the hi g h er the
the s o f t e r was the baked
(r = + .4 01)
i n d i c a t e d the
panel ass oci ate d good f l a v o r with moistness which has been described as
being a t y p i c a l
(40, 43, 44,
r e a c t i o n o f t a s t e panels in the southern U n it e d States
112).
Inheri tance o f Flavor
_
The data showing the d i s t r i b u t i o n o f the number of sweet potato
seedlings o f each progeny into d i f f e r e n t f l a v o r classes are presented
in Table 23 and the percentage o f seedlings in each class
Table 24.
(Table 2 ) .
is given in
The f l a v o r d i f f e r e n c e s among the pa re n ts were q u i t e
The progeny means in T ab le 23 v a r i e d c on si d er ab ly .
large
In a l l
crosses the progeny mean va r ie d from a point approaching the mean o f the
parents to well
below t h a t of the low parent.
Very few i n d i v i d u a l s
in
any given progeny possessed a f l a v o r superior t o t h a t of the b e t t e r pa­
rent but many had a f l a v o r
i n f e r i o r to th at o f the poorer p a r e n t .
Transgressive segregation occurred in a l l
crosses.
nature o f f l a v o r and the personal preferences o f
The s u b j e c t i v e
in di v id u a l
panelists
makes ac cu ra te c l a s s i f i c a t i o n o f f l a v o r d i f f i c u l t but the d at a obtained
i n d i c a t e t h a t d e s i r a b l e f l a v o r is a recessive t r a i t .
Co-variance
TABLE 23:
Parentaqe
Class * 1
2
Frequency D i s t r i b u t i o n o f Number o f Sweet P o ta to S e e d lin g s o f
Each Progeny i n t o Classes Based on F la v o r o f th e Baked Roots
3
4
5
6
7
8
2
Zi
1
2
9
10
Progeny
Mean
Standard
Error
6.1
0.47
L3-80 x L3-77
1
L3-77 (X)
1
3
8
7
1
5.2
0.21
3
4
b
7
1
4.7
0.32
2
b
5
2
4.5
0. 36
2
7
2
3
3
5.1
0. 36
2
6
8
10
3
5.2
0.21
2
5
1
7
5
4.7
0.40
6
34
22
9
5.4
0.13
5.2
0.21
2
L3-77 x NC171
L3-80 (X)
L3 -7 7t x NCI71
'
Kandee (X)
L3-77t x L I 31
2
2
L3-77 x L l - 8 0
1
2
L3-77 x K
L3-77 x L3-80
L3-80 x K
2
1
4
8
8
14
6
9
25
28
bl
40
24
4
5.0
0. 12
7
7
6
4
2
5.4
0. 27
2
4
6
5.3
0. 22
2
5
1
4.9
0.35
1
K x L3-77
K x L3-80
1
1
1
C o ntinued
TABLE 23:
Parentaqe
Class* 1
2
L3-93 x L131
L3-93 x L I -80
3
L8-3 x L I -80
0K51 x L I 3 T
W.S. x L21
L9-39 x NCI71
*
1
Progeny
Mean
Standard
E rr or
5. 2
0. 16
b
5-3
0. 15
6
2
5-7
0.21
2
b
1
6.6
0.13
5
6
7
10
18
13
10
9
U .
22
28
13
2
b
8
13
1
1
4
6
?
L I - 171 x L131
L I 31 x L3-77
C o n tin u e d
.
8
9
1
10
1
2
b
8
11
5
2
5. 5
0.24
1
2
12
13
16
b
3
5.2
0.20
2
6
7
9
3
4.2
0. 22
I
2
2
1
4.9
0.50
1
Flavor was rated on a numerical scale from 1 to 10 where 1 = Very poor f l a v o r and 10 = Ex c e l le n t
flavor.
TABLE 24:
Parentage
Class*
I
2
Percentage o f Sweet Potato Seed 1ings of Each Progeny in
D i f f e r e n t Classes Based on Fl av or of the Baked Roots
4
3
10.0
■.
6
7
20.0
40.0
10.0
15.0
40.0
35.0
5.0
14.3
19.0
19.0
33.3
4.8
L3-80 (X)
15.4
30.8
38.5
15.4
L3-77t x NC171
11.1
38.9
11.1
16.7
16.7
6.9
20.7'
27 .6
34.5
10.3
20 . 8
4.2
29.2
20.8
8.1
45.9
29.7
12.2
L3-77 (X)
L3-77 x NC171
9.5
Kandee (X)
L3-77t x L131
8.3
8. 3
L3-77 x L ! -80
1 .k
2.7
L3-77 x K
L3-77 x L3-80
L3-80 x K
1.1
•
5.0
00
L3-80 x L3-77
5
8
■ 20.0
5.6
2.4
9.8
19.5
19.5
34.1
14.6
5.2
14.4
16.1
24.1
22.9
13.8
2.3
25 .9
25.9
22.2
14.8
7.4
16.7
33.3
50.0
3-7
K x L3-77
K x L3-80
10.0
20.0
50 .0
10.0
10.0
L3-93 x L131
10.5
17.5
31.6
22.8
17.5
C o ntin u e d
TABLE 24:
Parentage
Cl ass * 1
L3-93 x L I -80
2
3.3
L8-3 x L I -80
3
0K51 x L I 31
W.S. x L21
L9-39 x NCI71
*
1.9
5
6
7
8
10.0
12.2
24.4
31.1
14.4
4.5
5.7
11.4
22 .9
37.1
17.1
5. 7
10.0
10.0
20.0
40. 0
10.0
LI-171 x L131
L131 x L3-77
4
C o n tin u e d
3. 0
6.1
12. 1
24 .2
33.3
15.2
6.1
1.9
3.8
23.1
25 .0
30 .8
7. 7
5.8
7.4
22 .2
25.9
33-3
11.1
14.3
28.6
28.6
14.3
14.3
Flavor was rated on a numerical scale from 1 to 10 where 1 = Very poor f l a v o r and 10 = E x c e l l e n t
flavor.
TABLE 25:
Parentaqe
Class* 1
L3-80 x L3-77
2
L3-77 x L I -80
2
L3-77 x K
K x L3-77
1
2
2
4
l
2
9
10
Progeny
Mean
Standard
Error
5.9
0. 62
5.1
0. 26
6
5
1
6
5
4.6
0.33
3
5
4
1
4.2
0.26
3
7
3
2
3
1
5
9
9 >
5
5.4
0. 20
2
5
3
6
4
4.6
0.38
1
9
30
22
10
5.2
0.14
4
2
9
8
15
3
5.2
0. 22
14
22
35
42
34
18
M .
0.12
2
1
7
7
4
6
5.0
0.28
4
5
1
5.7
0.36
Kandee (X)
2
7
8
6
1
L3-77t x L I 31
6
4
L3-80 (X)
L3-77t x NCI71
5
2
4
L3-77 x NCI71
L3-80 x K
?
4
1
L3-77 (X)
L3-77 x L3-80
Frequency D i s t r i b u t i o n o f Number o f Sweet P o ta to S e e d lin g s
o f Each Progeny i n t o D i f f e r e n t C lasses Based on Sweetness
o f th e Baked Roots
2
1
1
7
1
k‘1
0. 36
Cont i nued
CD
VO
TABLE 25:
Parentaqe
C la ss * 1
2
K x L3-80
C o n tin u e d
5
6
7
1
4
2
2
3
4
l
8
9
10
Progeny
Mean
Standard
Er ro r
5. 3
0.40
L3-93 x L131
1
9
7
19
14
5
2
5.0
0.18
L3-93 x L I -80
4
5
16
19
27
14
5
5.4
0. 1 5
4
2
11
9
7
2
5.5
0.23
4
1
2
6.4
0.52
L8-3 x L I -80
2
Ll-171 x L131
l
• 1
4
3
9
8
7
1
5.3
0.26
0K51 x L I 31
1
1
2
12
15
15
6
6.1
0.1 8
W.S. x L21
2
6
8
9
2
4.6
0.21
I
2
1
2
5.0
0.53
L131 x L3-77
L9-39 x NCI71
*
•
1
Sweetness was rated on a numerical scale from 1 to 10 where 1 = B i t t e r and 10 = Very sweet.
TABLE 26:
Parentage
Class*
L3-80 x L3-77
1
2
Percentage o f Sweet P o ta to S e e d lin g s o f Each Progeny in
D i f f e r e n t Classes Based on Sweetness o f th e Baked Roots
3
4
10.0
2.7
40.0
10.0
23.8
4.8
28.6
23 .8
23.1
38.5
30.8
7.7
16.7
38 .9
16.7
11.1
16.7
3.4
17.2
31. 0
31.0
17.2
8.3
20. 8
12.5
25.0
16.7
1.4
12.2
40.5
29.7
13.5
9.8
4.9
21.9
19.6
36 .6
7.3
8.0
12.6
20,1
24.1
19.5
10.3
7.4
3.7
25 . 9
25.9
14.8
22 .2
33.3
41 .7
8. 3
40.0
20 .0
20.0
Kandee (X)
L3-77 x L I -80
20.0
30 .0
5.6
8. 3
20.0
30 .0
L3-80 (X)
L3-77t x L I 31
7
20.0
19.0
L3 -77t x NCL71
6
10.0
L3-77 (X)
L3-77 x NC171
5
8. 3
8
10.0
5.6
<
L3-77 x K
L3-77 x L3-80
L3-80 x K
0.6
K x L3-77
8.3
K x L3-80
10.0
10.0
4.0
8.3
Cont i nued
TABLE 26:
Parentage
Cl ass * 1
2
3
4
C o n tin u e d
5
6
7
8
L3-93 x LI 31
1.8
15.8
12.3
33.3
24.6
8.8
3.5
L3-93 x L I -80
4.4
5.6
17.8
21.1
30.0
15.6
5.6
11 .4
5-7
31.4
25-7
20.0
5.7
40.0
10.0
20.0
3.0
L8-3 x L I -80
20 .0
LI-171 x L131
L I 31 x L3-77
0K51 x LI 31
I
W.S. x L21
L9-39 x NC171
*
1.9
3.0
12.1
9.1
27.3
24. 2
21.2
1.9
3.8
23.1
28 . 8
28.8
11.5
7.4
22.2
29 .6
33.3
7.4
14.3
28 .6
14.3
28.6
9
14.3
Sweetness was rated on a numerical scale from 1 to 10 where I « B i t t e r and 10 = Very sweet.
10
93
analyses i n di c at ed t h a t carotene and f l a v o r
and f l a v o r
flav o r
(r = + . 217) and moistness
(r = + . 4 0 1 ) were p o s i t i v e l y ass oci ate d w h i l e dry m at te r and
(r = -.1 2 2 )
appeared to be n e g a t i v e l y associated
(Table 3 5 ) .
Inher i tance o f Sweetness
Data showing the frequency d i s t r i b u t i o n o f the see dlings o f each
progeny f o r sweetness o f the baked roots i n t o d i f f e r e n t classes are
shown in Table 25 and the percentage o f se ed lin gs in each class
in T ab le 26.
Kandee, L3-77 and L3-80 were crossed in a l l
b i n a t i o n s with one ano the r.
is given
p o s si b le com­
In a d d i t i o n the cross o f L3-77 * L 131 and
its '
r e ci pr oc al were made.
In each of these crosses, when a parent
high
in sweetness was used as the male the progeny mean score f o r sweet­
ness was higher than when the p ar en t low in sweetness was used as the
male.
In each progeny the mean score f o r sweetness was e i t h e r
d i a t e compared to the parents o r
i n f e r i o r to the poorer p a r e n t .
g r e s s i v e seg regation occurred as shown by the presence,
interme­
Trans-
in each progeny,
o f see dlings r at ed hi gh er and seedlings r a t e d lower than e i t h e r p a r e n t.
Sweetness and f l a v o r had a close r e l a t i o n s h i p as shown in Tab le 35 by
the c o r r e l a t i o n c o e f f i c i e n t
al s o p o s i t i v e l y c o r r e l a t e d
dered w ith e a r l i e r
research
(r = + . 8 1 9 ) .
( r = + . 676) .
Moistness and sweetness were
Thi s r e l a t i o n s h i p , when consi­
(40, 44, 57, 5 8 ,
tance o f c e r t a i n enzyme systems.
Sweetness,
112) suggests the i n h e r i ­
like fla v o r,
is apparently
a re ce s s i v e c h a r a c t e r .
In h er i tance o f F i rmness
The frequency d i s t r i b u t i o n o f the sweet potat o seedlings o f each
progeny into d i f f e r e n t classes based on the firmness o f the baked roots
is presented in Ta b le 27.
The percentage o f seedlings
in each class is
TABLE 27:
Frequency D i s t r i b u t i o n o f Number o f Sweet P o ta to S e e d lin g s o f
Each Progeny i n t o D i f f e r e n t C lasses Based on F irm n e s s * o f the
Baked Roots
Class
Parentage
5
Very
Fi rm
V ery
Fi rm
L3-80 x L3-77
Medium
Soft
So ft
Progeny
Mean
Standard
Er ror
3
2
5
4.3
0.51
L3-77 (X)
b
5
3
b
3. 0
0.32
L3-77 x NC171
7
7
3
b
3.2
0.25
1
1.9
0. 37
2.6
0. 2 6
2
2. 7
0.16
L3-80 (X)
6
3
2
1
L3- 77t x NC171
3
7
3
5
Kandee (X)
1
15
L3-77t x L131
8
L3-77 x L l - 8 0
L3-77 x K
L3-77 x L3-80
L3-80 x K
K x L3-77
11
b
5
10
3.8
0. 26
7
9
1b
3.8
0 . 19
2
11
12
9
7
3-2
0.18
13
37
37
32
18
3.0
0.10
5
7
8
6
3.5
0.2 2
b
3
b
3.8
0. 30
Cont i nued
vo
-c-
TABLE 27:
Class
Parentaqe
1
Very
Firm
2
3
F i rm
Med i urn
C o n tin u e d
4
Soft
5
Very
S o ft
Progeny
Mean
Standard
Error
4
2
3
3.6
0. 40
10
11
16
15
3-5
0.17
10
15
22
31
12
3. 2
0 .13
L8-3 x L I -80
3
3
12
10
7
3.4
0.20
LI -171 x L131
1
1
2
3
3
3. 6
0.43
L 13 1 X L3-77
5
3
10
7
8
3.3
0.24
0K51 x L I 31
4
6
20
13
9
3.2
0. 16
W.S. x L21
8
8
8
3
2. 2
0.19
2
3
1
3.1
0. 40
K x L3-80
1
L3-93 x L I 31
5
L3-93 x L I -80
L9-39 x NCI71
*
1
Firmness class values were obtained using the ASCO firmness meter.
96
TABLE 28:
Class
Parentaae
Percentage o f Sweet Potato Seedlings of Each
Progeny in the D i f f e r e n t Classes Based on
Firmness* of the Baked Roots
1
Verv Firm
2
F i rm
3
Med i urn
1
4
S o ft
5
Very So ft
30. 0
20.0
50 . 0
20.0
25.0
15.0
20.0
33.3
33.3
14.3
19.0
46.2
23.1
15.4
7.7
7-7
16.7
38 .9
16.7
27.8
Kandee (X)
3.4
51. 7
37-9
L3 -7 7t x L131
4.2
16.7
16.7
20.8
41.7
21.1
18.4
23.7
36.8
L3-30 x L3-77
L3-77 (X)
20.0
L3-77 x NCI71
L3-80
(X)
L3 -7 7t x NC171
L3-77 x L I -80
6.9
L3-77 x K
4.9
26 .8
29.3
21.9
17.1
L3-77 x L3-80
9.5
27.0
27 .0
23.4
13-1
L3-80 x K
3.7
18.5
25.9
29.6
22.2
8.3
33.3
25.0
33-3
40.0
20.0
30.0
K x L3-77
K x L3-80
10.0
8.8
17.5
19.3
28.1
26.3
*11.1
16.7
24 . 4
34.4
13.3
8.6
8.6
34.3
28.6
20.0
L 1- 171 x L 131
10.0
10.0
20 .0
30.0
30.0
L I 31
X
L3-77
15.2
9.1
30.1
21.2
24.2
0K51
X
L i 31
7.7
11.5
38.5
25.0
17-3
29.6
29 .6
29 . 6
11.1
28.6
42.9
14.3
L3-93 x L I 31
L3-93 x L I -80
L8-3 x L i - 8 0
W.S. x L21
L9-39 x NC171
14.3
* Firmness class values were obtained using the ASCO firmness meter.
given in Table 28.
stances they f e l l
a suprisingly
The progeny means v a r i e d widely but in most i n ­
between t h a t o f the two pa r e n ts .
large number o f
i n d i v i d u a l s were in classes k and 5 ,
which in d ic a t e d r a t h e r s o f t r o o t s .
w e ll
In most progenies,
In several
above 50 per cent o f the progeny.
cases t h i s number was
This skewing o f the data is
exp laine d by s e l e c t i o n pressure e xe rte d throughout the breeding pro­
gram to o b t a i n roots t h a t were s o f t when baked.
W h i te s ta r a*>d L2T
were not developed f o r baking purposes and both parents were f i r m
when baked.
When these two paren ts were crossed, the progeny
x L21) mean was 2 . 2 or f i r m .
Approximately 60 per cent of the progeny
was c l a s s i f i e d as e i t h e r f i r m or very f i r m .
were c l a s s i f i e d as medium in fir m nes s.
x L3-80 and i t s 1 r e c i p r o c a l
(W.S.
Kandee, L3-80 and NC171
The progeny o f the cross Kandee
di d not appear to d i f f e r from the progenies
o f s o f t or very Soft par en ts ; however, both p ar en ts , when s e l f e d , pro­
duced progenies w it h roots t h a t were f i r m when baked.
In most pr o ­
genies there were seedlings w it h roots t h a t were s o f t e r and seedlings
w it h roots t h a t were f i r m e r than e i t h e r paren t when baked.
The c o r r e l a t i o n c o e f f i c i e n t s are presented in Table 35-
There was
no r e l a t i o n between shape and firmness
(r = + .0 2 3 ).
te x thickness had an r value o f - . 1 3 6 ,
s i g n i f i c a n t a t the 1 per cent
le v e l
but i t was o f a low magnitude.
and firmness,
correlated.
Carotene and fir m nes s, dry matter
and moistness and firmness were a l l
Carotene and firmness
Firmness and cor ­
( r = + .5 1^ )
fa irly
c lo s e l y
and moistness and f i r m ­
ness ( r = + .6 9 2 ) were p o s i t i v e l y ass oc ia te d, which i n d ic at es t h a t as
carotene or moistness increases the roots become less f i r m .
and firmness
Dry matter
( r = - . 5 ^ 1 ) were n e g a t i v e l y associated o r as dry ma tter
increased the roots became more f i r m .
Although firmness and f i b e r
1
2
L3-80 x L3-77
\D
O
1
m
o
CA
2
5
6
7
00
in
CM
0•
I
LTV
CM
1
1
O
cm
1
00
o'
1
2
2
CM
1
CM
1
00
•
o
1
O
o
Standai
Err or
0.746
.542
1.907
.627
1.216
.390
1
2
3
A
2
5j
2
6
2
1
1
2
1
1
1.710
.884
2
1
1
2
8
2
1.086
.526
2
1
4
3
3
4
5
1.503
.907
2
1
1
2
2
A
5
3
1.503
.907
3
2
5
2
6
17
19
11
6
2
1.204
.111
1
1
1
3
7
4
5
5
12
2
1.097
.173
20
8
12
11
33
25
20
22
20
A
1.402
1
3
1
1
3
4
5
7
2
0.926
.101
2
L3-77 x NCI71
1
1
L3-80 (X)
2
2
L3-77 1 x NCI71
2
Kandee (X)
5
L 3- 77 t x L131
4
L3-77 x L I -80
L3-77 x K
1
2
Continued
LA
6
00
o
1
Progeny
Mean
1
2
L3-80 x K
10
5
L3-77 (X)
L3-77 x L3-80
9
4
3
-aPer Cent ^
Fiber
^r
Percentage
^
oo
Class
Frequency D i s t r i b u t i o n o f Number o f Sweet P o ta to S e e d lin g s o f
Each Progeny i n t o D i f f e r e n t C lasses Based on P ercentage F i b e r
i n th e Baked Roots
0.6-0.8
TABLE 29:
^
oo
TABLE 29:
Class
Per Cent
F ib er
Parentage
1
^
oi
2
7/
«
-S'•
0*4
6
•
CM
•
C-J
I
0D
*
4
oo
1
in
K x L3-77
5
vn
•
C o n tin a e d
6
CM
•
CM
«
1
1
O•
2
2
1
7
o
•
1
oo
*
o
fl"
OO
•
o
i
vD
•
O
3
9
10
0
1
cn
o
m
•
0
1
o
*
o
it
]
0.760
. 110
it
1
l.W t
.791
vO
•
Progeny
Mean
Standard
Err or
K x L3-80
1
L3-93 x L13I
8
2
5
4
10
6
6
10
5
1
1.409
.111
L3-93 x L I -80
6
1
2
2
7
16
6
19
25
6
1.050
.117
L8-3 x L I -80
1
1
4
5
5
6
it
9
1.049
.102
LI-171 x LI31
2
1
I
1
2
3
1.601
.141
L131 x L3-77
7
2
2
3
3
3
2
5
5
1.516
.173
0K51 x L131
9
4
3
11
7
2
7
it
it
1.861
.195
L9-39 x NCI71
1
3
1
W.S. x L21
1
3
it
4
3
5
1
1
1
1
1.249
.863
8
1
1.013
.119
vo
vo
Class
Per Cent
Fi b er
Parentage
2
1
3
-d-
0.
3
CM
1
-T
»
CM
CM
1
CO
4
5
00
LA
1
LA
1
CM
CM
7
JO.O
L3-80 x L3-77
L3-77 (X)
Percentage o f Sweet Potato Seedlings o f Each Progeny in
D i f f e r e n t Classes Based on Percentage F i b e r in the Baked
Roots
1.0-1.2
TABLE 30:
■
9
10
CO
v£>
0
O
CTi
0
1
0*
0
1
00
1
VO
CA
o’
0
O
*
20.0
20.0
50.0
10.0
5-0
30.0
5.0
10.0
15.0
19.0
9-5
23.8
9.5
28.6
12.5
6. 3
6.3
12.5
6.3
10.5
5.3
5.3
10.5
42.1
10-5
6.9
3 -4
13.8
10.3
10.3
13.8
17.2
10.0
10.0
0
8
5.0
4.8
4.8
L3-80 (X)
12.5
12.5
L3-77t x NCI71
10.5
Kandee (X)
17.2
L3-77t x L131
16.7
8.3
4.2
4.2
8.3
8. 3
16.7
20.8
12.5
L3-77 x L I -80
4.1
2.7
6.8
2.7
8. l
22 .9
25.7
14.9
8.1
2. 7
L3-77 x K
2.4
2.4
2.4
7.3
17.1
9.8
12.2
12.2
29-3
4.9
11.4
4.6
6.9
6.3
18.9
14.3
11.4
12.6
11.4
2.3
3.7
3.7
11.1
14.8
18.5
25 .9
7-4
L3-77 x NC171
L3-77 x L3-80
L3-80 x K
3.7
6.3
11.1
Conti nued
6.3
6.9
TABLE 30:
Class
Per Cent
Fi be r
Parentage
1
CL
2
-cr
CM
1
•
CM
3
.•
cM
1
OO
•
CM
C o ntinue d
4
5
oo
—
1
IA
—*
LT\
K x L3-77
6
7
8
9
10
CM
o
—
_
00
o
1
vD
O
1
CA
O
rA
O
1
O
«
o
33.0
8. 3
40.0
10.0
*
1
CM
—'
16.7
1
O
*
1
00
o
o
25-0
16.7
10,0
VO
K x L3-80
10.0
L3^93 x L I 31
13.8
3. 4
8. 6
6.9
17.2
10.3
10.3
17.2
8. 6
1.7
L3-93 x L I -80
6.7
1.1
2. 2
2.2
7.8
17.8
6. 7
21.1
27.8
6.7
L8-3 x L I -80
2.9
2.9
11.4
14.3
’4.3
17.1
11.4
25.7
L I -171 x L131
20.0
10.0
10.0
10.0
20.0
LT31 x L3-77
21 .2
6.1
6.1
9.1
9.1
9.1
6. l
15.2
15-2
0K51 x LI 31
16,7
7.4
5-6
20 .4
13.0
3. 7
13.0
7.4
7.4
L9-39 x NCI71
14.3
42.9
14.3
11.1
14.8
Whi t e s t a r x L21
3.7
14.8
30.0
18.5
30.0
3. 7
3.0
14.3
14.3
29 .6
3-7
102
content had a s i g n i f i c a n t r value, + . 0 9 9 .
practical
it
is too low to be o f a
val ue.
Firmness,
l i k e ca r o t en e , dry m a t te r and moistness, appeared to
be a q u a n t i t a t i v e ch a ra c t e r c o n t r o l l e d by several
transgressively.
genes, segregating
The high r values in the a s s o c i a ti o n o f some charac­
t e r s could i n d i c a t e some l in k ag e.
Inher i tance o f F i ber
The frequency d i s t r i b u t i o n o f the sweet p o t a t o seedlings o f each
progeny in to d i f f e r e n t classes based on the percentage f i b e r
in the
baked roots is presented in Table 29 and the percentage o f seedlings
in each class
is given in Tab le 30.
In every progeny the mean f i b e r
content was higher than the parent w it h the g r e a t e s t f i b e r con tent;
however,
th ere were some seedlings w i t h
with the lowest f i b e r c o n te n t.
less f i b e r than the parent
The p a r e n ta l
l i n e s ranged in f i b e r con­
t e n t from a low o f 0.301 per cent to a high o f
2).
1.106 per cent
Several progenies contained i n d i v i d u a l s w it h
(Table
less than 0 . 2 0 per
cent f i b e r and one i n d i v i d u a l
in the progeny o f L3-77 s e l f e d contained
more than 13 per cent f i b e r .
Three p a r e n t s , Kandee, L3-77 and L3-80
were s e l f e d and crossed in a l l
p o s si b le combinations w it h one another.
In the s e l f e d progenies the mean f i b e r content was from 3 to k times
t h a t o f the p a r e n ts .
cal,
In the cross o f Kandee x L3-77 and i t s *
recipro­
the female appeared to e x e r t a st ro nge r i n fl u e n c e on the f i b e r
content o f the progeny.
The male p a r e n t appeared to have the g r e a t e r
i n f l u e n c e in the cross Kandee x L3-80 and i t s '
r e c i p r o c a l and in the
cross L3-77 * L3-80 and i t s 1 r e c i p r o c a l .
F i b e r content appeared to be a q u a n t i t a t i v e c h a r a c t e r c o n t r o l l e d
PLATE 9:
F i b e r Content in 25 Grams of Baked Root Tis sue in
Each o f Two Seedlings o f L3-1 7 x Kandee Progeny.
S ee dl ing w it h Lowest F i b e r Content ( l e f t ) and
S ee dl ing w it h Highest F i b e r Content ( r i g h t )
104
by
several
genes, geometric in e f f e c t ,
segre gat ing t r a n s g r e s s i v e l y .
A l l o f the parents used in t h i s study were apparently very h e t e r o z y ­
gous f o r f i b e r .
No maximum l i m i t has been e s t a b l i s h e d f o r an acc ept a­
ble f i b e r content in sweet p o t a t o e s .
Sc h m it t, e t a^ (91) proposed a
l i m i t o f 0 . 5 per cent f o r asparagus.
Several o f the parents in t h i s
study were commercial
con ten t.
sweet p o t a t o v a r i e t i e s and they v a r i e d in f i b e r
Kandee was the lowest w it h 0.301
per cent f i b e r and NC171
(Nugget) was the h i g h e s t with 1.1 06 per cent f i b e r .
contained 0.631 per cen t f i b e r ,
L8-3 ( J u l i a n )
L 3 - 77 (C en te nn ial )
contained 0.775 per cent
f i b e r and W h i te s ta r contained 0.741 per cent f i b e r .
I f a maximum f i b e r
content was e s t a b l i s h e d between 0 . 5 0 and 0 . 7 5 the p l a n t breeder would
have no major problem in s e l e c t i n g seedlings with low f i b e r con ten t as
shown by the number o f seedlings
30).
P l a t e 9 shows th e t o t a l
in classes 8 , 9 and 10 (Tables 29 and
amount of f i b e r from a 25 gram sample of
baked root t is s u e removed from the lowest and highest i n d i v i d u a l s o f
the progeny L3-77 x Kandee.
P i a t e 10 is s i m i l a r to P l a t e 9 except
the see dlings are from the progeny of 0K51 x L 131 The frequency d i s t r i b u t i o n o f the sweet potato seedlings o f each
progeny i n t o d i f f e r e n t f i b e r s i z e classes
is given in Table 31 and
the percentage o f se ed lin gs in each class
is given in Table 32.
The
f i b e r s were c l a s s i f i e d f o r s i z e based on the approximate diameter o f
the i n d i v i d u a l
f i b e r s as i l l u s t r a t e d in P l a t e
The length o f the
i n d i v i d u a l f i b e r s was not considered in t h i s study.
In most progenies the mean f i b e r s i z e was between t h a t of the two
parents and was u s u a ll y nearer t h a t of the female p a r e n t .
geny t h er e were see dl in gs w it h f i b e r s
those o f the p a r e n t s .
l a r g e r and s m a l le r
In each pro­
in s iz e than
In most progenies the number l a r g e r than t h a t of
PLATE 10:
F i b e r Content in 25 Grams o f Baked Root Tissue in
Each of Two Seedlings o f 0K51 x L131 Progeny.
Seedling w i t h Lowest F i b e r Content ( l e f t ) and
Seedling w i t h Highest F i b e r Content ( r i g h t )
TABLE 31:
Class
Parentage
1
Very
Coarse
Frequency D i s t r i b u t i o n o f Number o f Sweet P o ta to S e e d lin g s
o f Each Progeny i n t o D i f f e r e n t Classes Based on F i b e r S iz e
2
Coarse
3
Medium
4
Fine
5
Ve ry
F i ne
Progeny
Mean
Standard
Error
L3-80 x L3-77
1
2
4
2
1
3.0
0.37
L3-77 (X)
3
2
5
8
2
3. 2
0.28
L3-77 x NCI71
3
6
6
3
3
2.9
0.28
L3-80 (X)
4
3
3
3
2.4
0.33
L 3- 77 t x NCI71
1
5
6
5
1
2.8
0.24
Kandee (X)
7
7
9
5
1
2.5
0.21
L 3- 77 t x L I 31
4
6
7
5
2
2.8
0. 2 5
L3-77 x L I -80
2
7
11
10
8
3.4
0.19
L3-77 x K
8
12
13
3
5
2.6
0.19
12
30
48
33
14
3.1
0.09
L3-80 x K
1
3
10
8
5
3. 5
0.20
K x L3-77
4
2
1
3
2
2.8
0.46
K x L3-80
2
1
2
4
1
3.1
0.4 3
L3-77 x L3-80
Continued
TABLE 31:
Class
1
Very
Pa rentage_______________ Coarse
L3-93 x L I 31
L3-93 X L l - 8 0
2
3
Coarse
Medium
5
Very
Progeny
Standard
F i ne_________Mean___________________ Error
F i ne
1**
16
8
5
2.6
0.17
4
9
26
33
18
3.6
0.11
7
13
9
5
3.3
0.18
3
2. 0
0.26
0.2if
1
LI-171 x L131
3
if
LI 31 x 13-77
8
5
17
W.S. x L21
L9-39 x NC171
^
l*t
L8-3 x L l - 8 0
0K51 x L131
C o ntin u e d
17
1
2
8
8
if
2.8
10
7
1
2.1
5
13
2
1
5
1
3
1
.
0. 15
3.1
0.19
2.6
0.57
108
TABLE 32:
P e rcen tag e o f Sweet P o ta t o S e e d lin g s o f
Each Progeny in D i f f e r e n t C lasses Based
on F i b e r Size
Class
1
2
3
4
Parentage________Very Coarse Coarse_____ Medium________Fine
5
Very Fine
L3-80 x L3-77
10.0
20.0
40.0
20 .0
10.0
L3-77 (X)
15-0
10.0
25.0
40.0
10.0
L3-77 x NC171
14.3
28 .6
28 .6
14.3
14.3
L3-80 (X)
30.8
23.1
23 -1
23.1
5.6
27.8
33-3
27.8
5.6
Kandee (X)
24.1
24.1
31.0
17.2
3.7
L3-77t x L i 31
16.7
25 .0
29.2
20.8
8.3
L3-77 x L l - 8 0
5.3
18.4
28.9
26.3
21.1
19.5
29.3
31 .7
7-3
12.2
L3-77 x L3-80
8.8
21.9
35 .0
24.1
10.2
L3-80 x K
3.7
11.1
37 .0
29 .6
18.5
K x L3-77
33.3
16.7
8.3
25 .0
16.7
K x L3-80
20.0
10.0
20 .0
40.0
10.0
L3-93 x L131
24 .6
24 .6
28.1
14.0
8.8
L3-93 x L l -8 0
4.4
10.0
28.9
36 .7
20.0
L8-3 x L l - 8 0
2.9
20.0
37.1
25.7
14.3
Ll-171 x L131
30.0
40.0
30 .0
L131 x L3-77
24 .2
15.2
24 .2
24 .2
12. 1
0K51 x L131
29.8
29.8
19.2
13.5
1.9
3.7
18.5
48.1
18.5
11.1
28.6
28 .6
14.3
14.3
14.3
L 3- 771 x NC171
L3-77 x K
W.S. x L21
L9-39 x NCI71
109
the l a r g e s t pa re nt g r e a t l y exceeded the number smaller than th at o f the
sm allest p a r e n t .
C o r r e l a t i o n c o e f f i c i e n t s between f i b e r content and c e r t a i n o t h e r
c h a r a c t e r i s t i c s are presented in Table 35.
o f roots per p l a n t and percentage f i b e r
The r value f o r the number
(r = - . 179) i n d ic a t e d an inverse
r e l a t i o n s h i p between the two chara ct er s but i t was o f such low or de r o f
magnitude t h a t
i t would be o f l i t t l e p r a c t i c a l
between firmness and f i b e r content
of a very low magnitude.
The ne g at iv e na tu re o f the r e l a t i o n s h i p was
i n di c at ed in cr easing s o f t ­
The c o r r e l a t i o n values o f carotene and f i b e r content
(r = - . 07*0 and o f dry m at ter and f i b e r content
significant.
(r = + .0 8 3 ) were not
There was a s l i g h t a s s o c i a t i o n between c o r t e x thickness
and f i b e r content
(r = + . 0 9 3 ) but i t was too low to be o f
The smoothness o f the r o o t ,
importance.
t h a t is degree o f freedom from vei nin g and/
or c r a c k in g , and f i b e r content
(r = - . 2 1 5 ) were i n v e r s e l y r e l a t e d ,
the rougher roots had a g r e a t e r f i b e r co n te n t.
e arlie r,
The a ss o ci at io n
( r - - . 099 ) was also negative and
expected since increas ing values f o r firmness
ness o f the r o o t s .
valu e.
thus
As was pointed out
the smoothness data were not recorded in a manner to show an
as s o c i a ti o n o f smoothness w i t h f i b e r co n te n t.
c o r r e l a t i o n between shape o f the ro ot
f i b e r content
There was a f a i r l y high
(high length to wid th r a t i o )
and
( r = + .4 1 1 ) which in d ic a t e d t h a t the longer the root the
g r e a t e r was the f i b e r co n te n t.
There was a hi ghl y s i g n i f i c a n t c o r r e l a t i o n
total
f i b e r content and f i b e r s i z e .
per cent o f the v a r i a t i o n
This in d ic a t e d t h a t more than 40
in f i b e r content was due to the regression o f
f i b e r s i z e on f i b e r c o n te n t.
l in k e d .
( r = + . 638 ) between
Thus the ch a ra ct er s were separate but
F i b e r s i z e appeared to be c o n t r o l l e d by a small
number of
no
TABLE 33:
Frequency D i s t r i b u t i o n of Number of
Sweet Potato Seedlings of Each Pro­
geny i n t o D i f f e r e n t Classes Based
on the Baking Index
0-4
Poor
4.1-6.0
Medium
5
3
12
5.6
Kandee (X)
4
24
1
5.1
L3-80
5
6
2
5. 3
3
22
16
5. 5
28
86
60
5. 4
K x L3 -77
1
8
3
5. 5
K x L3 - 80
1
6
3
5.4
1
3
6
6.4
L3-80 x K
4
7
16
5.9
L3-77 x L131
3
12
9
5.6
Li 31 x L3-77
3
11
19
5.9
L3-77 x NC171
4
12
5
5.4
L3-77 x L l - 8 0
3
31
40
6.1
L3-93 x LT31
9
23
25
5.7
12
37
41
5.9
L8-3 x L l - 8 0
3
10
22
6.1
0K51 x LI 3 1
7
17
28
5-7
L I -171 x L I 31
1
1
8
6.5
W.S. x L21
9
15
3
4.4
L9-39 x NCI71
1
3
3
5. 7
L 3- 77 t x NC171
8
5
6
5. 0
Parentage
L3-77
(X)
(X)
L3-77 x K
L3-77 x L3-80
O
00
1
x L3-77
L3-93 x L l - 8 0
Baking Index
Class
6.1-10
Good
Progeny
Mean
111
TABLE 34:
Parentage
Class
Baking Index
P e rcen tag e o f Sweet P o ta t o S e e d lin g s o f
Each Progeny in D i f f e r e n t Classes Based
on th e Baking Index
Poor
0-4.0
Medium
4.1-6.0
Good
6.1-10
L3-77 (X)
25.0
15.0
60.0
Kandee (X)
13.8
82 . 8
3 -4
L3-80 (X)
38 .5
46 . 2
15.3
7.3
53-7
39 .0
16.1
49.4
34.5
K x L3-77
8.3
66.7
25 .0
K x L3-80
10.0
60.0
30. 0
L3-80 x L3-77
10.0
30.0
60.0
L3-80 x K
14.8
25 . 9
59.3
L3-77 x L 131
12.5
50. 0
37. 5
LI31 x L3-77
9.1
33.3
57 . 6
L3-77 x NC171
19.0
57,1
23.8
L3-77 x L l - 8 0
4.1
41.9
54.0
L3-93 x L 131
15.8
40.4
43.8
L3-93 x L [ - 8 o
13.3
41.1
45.6
8.6
28.6
62.8
0K5I x L 131
13.5
32 .7
53 . 8
LI -171 X LI 31
10.0
10.0
80.0
W.S. x L21
33 .3 ■
55.6
11.1
L9-39 x NC171
14.3
42.9
42.9
L3-77 x K
L3-77 x L3-80
L8-3 x L l - 8 0
112
genes, w it h p a r t i a l
character
dominance.
F i b e r con ten t behaved as a q u a n t i t a t i v e
i n v o l v i n g several genes, geometric in e f f e c t ,
s eg re ga tin g in a
tr a n s g r e s s i v e manner.
Inher i tance o f Baki nq 1ndex
Data prese nte d in Ta b le 33 g i v e the frequency d i s t r i b u t i o n o f the
sweet po t at o s ee dl in gs o f each progeny based on the baking index and the
percentage o f s ee dl in gs
in each cl ass
is given in Table 34.
Progeny
means i n d i c a t e t h a t as a whole, most o f the see dling s were o f average or
medium baking q u a l i t y .
A much g r e a t e r percentage o f the see dl in gs f e l l
in the good baking c l a s s i f i c a t i o n
progeny mean u s u a l l y
than in the poor c l a s s i f i c a t i o n .
lay between the means o f the two paren ts and,
most cases, n e a re r the p ar en t w ith the hi g h er mean.
parental
in
Since most o f the
l i n e s had been s e l e c t e d as having acc ept abl e baking q u a l i t y ,
t h i s skewing o f the data toward the more p r e f e r a b l e s i d e ,
sev era l
The
as was t r u e
in
c h a r a c t e r s , was to be expected.
C o r r e l a t i o n c o e f f i c i e n t s between baking index and the va ri ous qua­
lity
components were not c a l c u l a t e d .
pected i f
A cl os e a s s o c i a t i o n would be ex­
c o n s id e r a t i o n was given to the manner in which the baking i n ­
dex was d e r i v e d .
The data o f C o nst ant in
such a con cl u si on .
f l a v o r , moistness,
(24) g iv e very good support to
He showed very close c o r r e l a t i o n s between sweetness,
and c o l o r ,
from r = +.8 35 to r = + . 9 5 4 .
and the baking index w i t h r values ranging
Thus the i n h e r i t a n c e o f baking q u a l i t y
based on the i n h e r i t a n c e o f the var io us components t h a t
ty in the baked r o o t s .
49 , 58,
qua li t y .
72, 92)
is
influence q u a l i ­
As shown in t h i s and o t h e r st u d ie s
(24, 40, 44,
these c h a r a c t e r s are i n h e r i t e d and i n f l u e n c e baking
113
TABLE 35:
C o r r e l a t i o n C o e f f i c i e n t s between Some
V a r i a b l e s in the F] Progenies o f the
Twenty-one Parental Combinations
Variables
Number o f Roots and Shape ( L : W) R a t i o
-.09 4*
Number o f Roots and Smoothness
.176**
Number o f Roots and C a rot en e
.082 n . s .
Number o f Roots and Dry M a t t e r
-.067 n.s.
Number o f Roots and F i b e r C o n te n t
-.1 7 9 **
Shape (L:W) R a t i o and Smoothness
-.0 3 0 n.s.
Shape (L:W) R a t i o and C o r t e x T h i c k n e s s
-.1 3 8 **
Shape (L:W) R a t i o and F ir m nes s
.023 n . s .
Shape (L:W) R a t i o and F i b e r C o n t e n t
.411**
Smoothness and
Cortex Thickness
-.061 n .s .
Smoothness and
C ar ot en e
.042 n . s .
Smoothness and
Dry M a t t e r
.007 n . s .
Smoothness and F i b e r C o n te n t
-.2 1 5 **
C o r t e x T h i c k n e s s and C a ro te n e
-.02 8 n.s.
C o r t e x T h i c k n e s s and Dry M a t t e r
.068 n . s .
C o r t e x T h i c k n e s s and F ir m nes s
-.13 6**
C o r t e x T h i c k n e s s and F i b e r C o n te n t
.093*
C a ro te n e and
Dry M a t t e r
-.5 6 9 **
Ca rot en e and
Moistness
.601**
Ca rot en e and
Flavor
.217*'*
Ca ro t e n e and
Color
Ca rot en e and
Firm nes s
In te n s ity
.941**
.514**
C o n ti n u e d
m
TABLE 35:
C o n tin u e d
V a ri a b l e s
r
Carotene and Fi ber Content
c
-3"
o•
1
Dry M at t e r and Moistness
-.57 2**
Dry M a tt e r and Fl av or
-.12 2**
Dry M at te r and Firmness
-.5 4 2 **
Dry M at te r and F ib er Content
.084 n.;
Moistness and Fla vor
.401**
Moistness and Firmness
.692**
. 676* *
10
F l a v o r and Sweetness
l
00
Moistness and Sweetness
Firmness and F i b e r Content
. 099*
F i b e r Content and F i b e r Size
. 638* *
*
S i g n i f i c a n t a t 5 per ce n t level
f o r 680 degrees of freedom.
**
S i g n i f i c a n t a t 1 per ce n t level
f o r 680 degrees of freedom,
n.s.
No s i g n i f i c a n t d i f f e r e n c e .
SUMMARY AND CONCLUSIONS
A study o f the i n h e r i t a n c e o f f i b e r ,
shape, c o r t e x thickness and baking q u a l i t y
dry m a t t e r , carotene content,
in sweet potat o roots was
conducted.
Twenty-one progenies obtained by se le ct ed combinations o f
14 p ar en ta l
li n e s and c e r t a i n s e l f e d paren ts were grown a t the Sweet
Potato Research Center, Chase, Lo u is ia na , harvested and tra ns po rt ed to
M is s is s ip p i
S t at e U n i v e r s i t y ,
for curing,
s t o r in g and e v a l u a t i n g the f a c ­
t or s st ud ie d.
The p r o g e n i e s v a r i e d w i d e l y
in p e r c e n ta g e o f t h e p l a n t s
that pro­
duced s t o r a g e r o o t s and in th e keep ing q u a l i t y o f th e r o o t s .
The l i n e
L8-3 ( J u l i a n )
appeared t o be s u p e r i o r as a female in t hes e r e s p e c t s .
Only 4 o f the 14 p ar en ta l
re n t s.
One l i n e ,
or female parent
roo ts .
li n e s were used as both male and female pa­
L3—77 ( C e n t e n n i a l ) , performed e q u a ll y well
as a male
in the a b i l i t y o f the seedlings to produce storage
Progenies in v o l v in g Kandee or L3-80 as one o f the parents i n d i ­
cated these two lin e s were b e t t e r as male parents than as female parents
w hi le L 131 appeared to perform b e t t e r as a female p a r e n t.
The pos sib le
presence o f cytoplasmic f a c t o r was suggested by these data.
An e v a l u a t i o n o f th e 21 p r o g e n i e s and 14 p a r e n t a l
o f th e r o o t as de te r m in e d by t h e l e n g t h : w i d t h
t h a t shape was a h e r i t a b l e c h a r a c t e r .
n a t u r e w i t h an absence o f dominance.
a d d itiv e e f fe c t.
l i n e s f o r shape
(L:W) r a t i o
in dica ted
S e g r e g a t i o n was t r a n s g r e s s i v e
in
The genes appeared t o have an
The d a t a i n d i c a t e d t h a t t h e s e l e c t i o n o f h i g h y i e l d i n g
p la n ts , plants w ith
l a r g e numbers o f e n l a r g e d r o o t s ,
115
and p l a n t s t h a t
116
produced w e l l
shaped r o o t s was p o s s i b l e w i t h o u t i n t e r a c t i o n o f t h e two
characters.
The p r o g e n ie s were e v a l u a t e d f o r s u r f a c e smoothness o f th e r o o t s
as an e s t i m a t e o f freed om from v e i n i n g and c r a c k i n g .
A l a r g e p e r c e n ta g e
o f th e s e e d l i n g s o f some p r o g e n i e s had r o o t s w i t h smooth s u r f a c e s .
fo rtu n a te ly,
the d a t a do not d i s t i n g u i s h
between the presence o f v e i n s
a n d / o r c r a c k s as causes f o r r a n k i n g th e r o o t s
p o s s i b l e cause f o r c r a c k i n g and i t s
in a p a r t i c u l a r c l a s s .
l o c a t e d between th e
The r e s u l t s o f t h i s study
t e x t h i c k n e s s was an i n h e r i t e d c h a r a c t e r .
p r o g e n i e s s e g r e g a te d i n a t y p i c a l
A
e f f e c t on smoothness was d i s c u s s e d .
The c o r t e x was c o n s i d e r e d as th ose t i s s u e s
e p i d e r m i s and e n d od er m is .
Un­
in d ic a te d th a t cor­
The s e e d l i n g s
t r a n s g r e s s i v e manner.
in th e v a r i o u s
R e la tive t h ic k ­
ness o f t h e c o r t e x appears t o be c o n t r o l l e d by r e l a t i v e l y few genes w i t h
s im p l e a d d i t i v e e f f e c t s .
In th e
i n h e r i t a n c e o f dr y m a t t e r ,
g re ssive segregation occurred.
t h e data i n d i c a t e d t h a t t r a n s -
In each progeny t h e r e were s e e d l i n g s
w i t h a dr y m a t t e r c o n t e n t h i g h e r than t h a t o f the h i g h e s t p a r e n t and
some t h a t were lo we r th an t h a t o f t h e l o w e s t p a r e n t .
In most p r o g e n i e s ,
t h e progeny mean was low er th an t h e mean o f th e two p a r e n t s p a r t i c u l a r l y
when both p a r e n t s were r e l a t i v e l y
t h a t dry m atter
in d r y m a t t e r .
I t was c on c lu de d
i s a q u a n t i t a t i v e c h a r a c t e r c o n t r o l l e d by s e v e r a l
l a c k i n g dominance b u t a d d i t i v e
manner.
high
in e f f e c t ,
genes,
segregating in a tra n s g re s s iv e
Dry m a t t e r was shown t o be p o s i t i v e l y c o r r e l a t e d w i t h m o i s t ­
ness , f i r m n e s s and f l a v o r .
In most p r o g e n i e s t h e mean c a r o t e n e c o n t e n t f e l l
parents,
between t h e two
u s u a l l y c l o s e l y a p p ro a c h in g th e mean o f t h e p a r e n t s combined.
Carotene c o n t e n t was a q u a n t i t a t i v e c h a r a c t e r t h a t s e g r e g a te d
117
transgressively.
The data i n d i c a t e t h a t several
suggested by Hernandez ( 4 9 ) ,
were a d d i t i v e in e f f e c t ,
genes, po s si b ly 6 as
c o n t r o l l e d carotene content.
lac ki ng dominance.
The genes
An e p i s t a t i c e f f e c t o f the
genes f o r wh ite co lo r over those f o r orange c o l o r or the presence o f an
i n h i b i t o r gene was suggested.
Carotene content was shown to be nega­
t i v e l y c o r r e l a t e d w ith dry m at ter and firmness but p o s i t i v e l y c o r r e l a t e d
wit h f l a v o r and moistness in the baked roots.
In g e n e r a l,
segregation f o r skin co lo r wast r a n s g r e s s iv e .
In a l l
progenies there were i n d i v i d u a l s l i g h t e r and darker in skin color than
e i t h e r p a r en t.
male p a r e n t ,
I f the female pa re nt had a l i g h t e r skin c o l o r than the
the g r e a t e r p a r t o f the seedlings in a progeny possessed
roots w it h a l i g h t skin c o l o r .
co lo r than the male,
I f the female paren t had a darker skin
the g r e a t e r p a r t o f the seedlings in a progeny
possessed roots with a dark skin c o l o r .
The darker the skin color o f
the parents the darker was the skin co lo r o f the roots o f the seedlings
in a progeny.
were a d d i t i v e
The data in d ic a t e d several
in e f f e c t ,
genes
were in vo lv ed .
some were complementary and
Some
o t h e r were i n h i b i -
t i ve.
The roots o f each seedling of each progeny were r at ed f o r baking
q u a lity .
The q u a l i t y o f the baked f l e s h o f sweet potato roots is i n ­
flue nced by carotene content
(or c o l o r ) ,
f ir m n es s , dry mat ter and f i b e r co n te n t.
sweetness, f l a v o r , moistness,
Thus the i n h e r i t a n c e o f q u a l i t y
in the sweet potat o is complex.
Color
intensity
in the baked roots was shown to be c l o s e l y c o r r e l a ­
ted to the carotene content o f the raw ro ot s.
Un if o r m it y o f the c o l o r
appeared to be c o n t r o l l e d by a r e l a t i v e l y small number o f genes t h a t
were a d d i t i v e
in e f f e c t w ith a t
le a s t p a r t i a l
dominance.
118
The d a t a i n d i c a t e d m o is t n e s s
c h a r a c t e r c o n t r o l l e d by s e v e r a l
i n the baked r o o t s was a q u a n t i t a t i v e
genes s e g r e g a t i n g t r a n s g r e s s i v e l y .
Dominance was n o t e v i d e n t ;
an a d d i t i v e e f f e c t was s ugg est ed .
M o is tn es s
was shown t o be p o s i t i v e l y
c o r r e l a t e d w i t h c a r o t e n e and f l a v o r b u t ne­
g a t i v e l y c o r r e l a t e d w i t h d r y m a t t e r and f i r m n e s s .
The f l a v o r data i n d i c a t e d t h a t the c o m b i n a t i o n o f c h a r a c t e r s
nec essary f o r a good o r s u p e r i o r f l a v o r was a r e c e s s i v e t r a i t .
fe w i n d i v i d u a l s
Very
i n any progeny possessed a f l a v o r o f sweetness s u p e r i o r
t o t h e b e t t e r p a r e n t b u t many were i n f e r i o r
t o t h e poo r p a r e n t .
was shown t o be c o r r e l a t e d w i t h c a r o t e n e , m o i s t n e s s ,
There was a n e g a t i v e a s s o c i a t i o n w i t h dry m a t t e r .
Flavor
and sweetness.
The i n h e r i t a n c e o f
th e genes c o n t r o l l i n g f l a v o r and sweetness was r e c e s s i v e and an a s s o c i a ­
t i o n w i t h one o r more enzyme systems as c o n v e r s i o n f a c t o r s d u r i n g ba ki ng
was sugg este d.
F ir m n e s s , c a r o t e n e ,
d r y m a t t e r and m o is t n e s s c h a r a c t e r s appeared
t o be q u a n t i t a t i v e and c o n t r o l l e d by s e v e r a l
gre ssive ly.
genes s e g r e g a t i n g t r a n s -
The h ig h degree o f c o r r e l a t i o n between some o f t h es e
c h a r a c t e r s suggested l i n k a g e as a f a c t o r .
V ariations
in f i b e r c o n t e n t o f th e s e e d l i n g s o c c u r r e d w i t h i n each
i n d i v i d u a l progeny b u t progeny means were s i m i l a r .
appeared t o be i n v o l v e d — one f o r
c o n t r o llin g f ib e r size .
f i b e r size w h ile t o t a l
Two s e t s o f genes
t h e pr es en ce o f f i b e r and a n o t h e r
A few genes w i t h s i m p l e dominance c o n t r o l l e d
f i b e r c o n t e n t was c o n t r o l l e d by s e v e r a l
g e o m e t r i c in e f f e c t and l i n k e d w i t h t h e genes f o r f i b e r
br e e d e r s ho u ld e n c o u n t e r no m aj or problems
size .
genes,
The p l a n t
in s e le c tin g seed lings w ith a
low f i b e r c o n t e n t .
The i n h e r i t a n c e o f b a k in g q u a l i t y
i s based on t h e i n h e r i t a n c e o f
119
the various components a f f e c t i n g q u a l i t y both i n d i v i d u a l l y and
collect iv e ly .
Although environment, p a r t i c u l a r l y p o s t - h a r v e s t han dling, was
known to in flu en ce the q u a l i t y of the baked roots,
t h a t baking q u a l i t y
is a h e r i t a b l e t r a i t .
by a complex of g e n e ti c c h a ra c t e r s ,
moistness,
dry m a t t e r ,
Baking q u a l i t y was c o n t r o l l e d
i nc lu din g c o l o r ,
firmness, and f i b e r , a l l
t i v e and segregated t r a n s g r e s s i v e l y .
t h i s study has shown
sweetness, f l a v o r ,
o f which were q u a n t i t a ­
BIBLIOGRAPHY
1.
A1 i , Mohammed Kasem.
1958.
The e f f e c t of v a r i e t y , length of s t o ­
rage, and the baking process on the carbohydrate content and
t a b l e q u a l i t y of sweet potatoes.
Ph.D. D i s s e r t a t i o n , La. S t at e
Univ.
141 p.
2.
Anderson, W. S.
1937.
The
of Triumph sweet potatoes
S c i . 35: 70 9- 7 12 .
3.
4.
5.
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qualityp.
Acomparative
Sweet Po tato Cooperative Group
AUTOBIOGRAPHY
H a rrell
Lee Hammett was born a t Ru s to n in L i n c o l n P a r i s h ,
Lo ui si ana on September 3,
tenant farm f a m i l y ,
1925.
He was reared as the o l d e s t son o f a
educated in the el em ent ar y and secondary schools of
L in co ln Pari sh and graduated from Choudrant High School
He was d r a f t e d
i n t o t h e U n i t e d S t a t e s Army I n f a n t r y
194-3 and served u n t i l
A p ril,
1946.
in May o f
1*942.
in O c t o b e r ,
He is married to the former Emma
Lee Boyd o f Choudrant, Louisiana and they are the parents of f ou r c h i l d ­
ren,
He en t er ed Lo u is i a n a P o l y t e c h n i c
September o f
1947.
1951 w it h majors
I n s t i t u t e , Ruston, Louisiana in
He rec e iv e d a Bac hel or o f Science degree in June,
in H o r t i c u l t u r e and Botany and a minor
in Agronomy.
He was employed by the United S t a t e s Department o f A g r i c u l t u r e ,
A g ric u ltu re M arketing Service,
Processed Products Inspection and
S t a n d a r d i z a t i o n as a processed food i n s p e c t o r working in Western
Tennessee from August, 1953 to August, 1957.
In August, 1957 he ac ce pt J
ed a p o s i t i o n w i t h M i s s i s s i p p i S t a t e U n i v e r s i t y and A g r i c u l t u r a l E x p e r i ­
ment S t a t i o n as A s s i s t a n t Pro fessor and A s s i s t a n t H o r t i c u l t u r i s t .
was promoted to the A s so ci at e rank in June,
In September,
1963 he was gra nt ed
U n i v e r s i t y and A g r i c u l t u r a l
Graduate School
19 6 1.
leave from M is s is s ip p i
S t at e
Experiment S t a t i o n and r e - e n t e r e d the
a t Lo u is ia na S t at e U n i v e r s i t y where he is p r e s e n tl y
a can did ate f o r the degree o f Doctor o f Philosophy.
129
He
EXAMINATION AND THESIS REPORT
Candidate: H a r r e l l Lee Hammett
Major Field: H o r t ic u l t u r e
T itle o f Thesis:
S tu d y o f th e I n h e r it a n c e o f R oot Shape, S k in C o lo r , T o t a l
C a ro te n o id P ig m e n ts , D ry M a t t e r , F ib e r and B a k in g Q u a lit y in
th e Sweet P o ta to (ipom oea b a ta ta s )
a
Approved:
.J&rv'LJLM ajor Professor and Chairm
irmani—~
<3
Dean of the Graduate School
E X A M IN IN G C O M M ITTE E :
m g.
Date of Examination:
J u ly 1 6 , 3.965 __
/■