Apple rootstock research
Emily Hoover
Professor, Department of Horticultural Science
University of Minnesota
Total Acres in Orchards 2002
www.nass.usda.gov/research/atlas02/index.html
The #1 reason for fewer orchards in
Minnesota?
Winter injury
Stunted growth
Dead trees
Split bark
USDA Hardiness
Zone Map
http://www.usna.usda.gov/Hardzone/hzm-nm1.html
Zone
2a
Fahrenheit
-50 to -45 F
Celsius
Example Cities
-42.8 to -45.5 C
Prudhoe Bay, Alaska;
Flin Flon, Manitoba
2b
-45 to -40 F
-40.0 to -42.7 C
Unalakleet, Alaska;
Pinecreek, MN
3a
-40 to -35 F
-37.3 to -39.9 C
International Falls, MN;
3b
-35 to -30 F
-34.5 to -37.2 C
Duluth MN;
4a
-30 to -25 F
-31.7 to -34.4 C
Minneapolis/St.Paul, MN;
4b
-25 to -20 F
-28.9 to -31.6 C
La Crescent MN; Nebraska
5a
-20 to -15 F
-26.2 to -28.8 C
Des Moines, Iowa;
St. Michael, Alaska
Sidney, Montana
Illinois
Lewistown, Montana
Orchards around 1890
Orchards today
Why rootstocks?
Impart characteristics to scion
(cultivar)
– Size control
– Uniformity in tree size
– Precocity, earliness to
flower
– Tolerance to cold
temperatures
– Resistance to soil borne
pests and diseases
– Increase in fruit size and
quality
Major Apple Rootstock Programs
• East Malling England (M, MM, EMLA)
• Poland (P)
• Russia (B, Bud) - Budagovsky series
• Canada - Robusta 5, Ottawa (Ott) and
Vineland (V)
• United States Cornell-USDA Geneva NY
(CG, G)
• Germany (Supp)
Regional Research Group –
NC140
• To evaluate the influence of rootstocks on
fruit tree characteristics
• To develop and improve rootstocks for
temperate-zone fruit trees
• To study the genetics and developmental
physiology of rootstock/scion interactions
• To better understand the response to and
impacts of biotic and abiotic stresses
NC-140 Locations
Minnesota is the
location with the
coldest winter
temperatures
Apple Rootstocks Evaluated
in MN
• Malling Series (England) – 4, 7, 9, 26,
106, 111
• Poland – 1, 2, 16, 18, 22
• Budagovsky series – 9, 490, 491
• Canada - Vineland 1, 3; Ott 3
• Geneva series – 10, 11, 24, 29,
30N,30T, 65, 202, 210, 935,814, 7707,
• Michigan – MARK, MAC 1 and 39
Data Collected
• Tree survival
• Tree characteristics
–
–
–
–
–
–
Trunk cross sectional area
Height and spread
Shoot growth
Branch angle
Trunk leaning
Burr knots
• Yield
– # flower clusters (first 2 years)
– Total kg/tree
– Fruit wt
How Minnesota Compares
• Trees are smaller than
most NC140 locations
• Cultivar is important!
• Harvest is delayed 2 to
3 years
• Yield is lower
Rootstock
TCA
(cm2)
Yield
(kg)
Yield efficiency
2
(g/cm )
CG935
25.7a
11.7a
483.1a
Supp 3
18.2abc
9.7a
542.1a
Supp 2
17.9abc
6.6a
512.3a
Supp1
12.8bc
4.7a
372.3a
M26
12.8bc
4.7a
319.1a
M9
12.0c
3.6a
312.3a
Growth (cm) of 1-year shoots of McIntosh grown on various
rootstocks, 4th leaf
CG935
SUPP3
SUPP2
SUPP1
M26
M9
0
5
10
15
20
25
30
35
40
45
Interested in the
relationship
between tree
growth (TCA
and shoot
growth) and
dwarfing
Questions?