2007 North Central Branch ASA
Annual Meeting & Conference
Indianapolis, IN
March 13-14, 2007
Wednesday - March 14
Session 3
8:30 to 10:00 am
Current Impact of Changes in Plant Density - Moderator: Steven
Paszkiewicz
• Physiological Impacts of Moderate- and High-Plant Densities in
Maize – Steven Paszkiewicz, Pioneer Hi-Bred Int’l, Inc., Research
Scientist
• Impacts of the Changing Planting Rates in Corn – Joe Lauer,
University of Wisconsin, Corn Extension Specialist
• Impacts of the Changing Seeding Rates in Soybean – Shawn
Conley, Purdue University, Soybean Extension Specialist
Physiological Impacts of Moderate- and HighPlant Densities in Maize
Steven R. Paszkiewicz, Ph.D.
Research Scientist
Pioneer Hi-Bred International, Inc.
Johnston, IA
Grain Yield (bu/ac)
Grain yield response to low and high plant populations
for hybrids from four eras of plant breeding, 2-year
average (Duvick, 1993).
150
125
plants/acre
4,000
32,000
100
75
50
25
0
1930s
1950s
1970s
Era Introduced
1990s
Physiological and grain yield responses to
plant populations up to 90,000 plants/acre
r
c
a
/
u
B
(
Grain yield response to plant population
for 5 hybrids, 5 locations.
d 220
l
e 200
i 180
Y
2000
2002
2001
1991
9
1994
18 27 36 45 54 63 72 81 90
Plant Population (x 1000)
Paszkiewicz et al., 2003
34G13
34H31
34M95
160
n
i 140
a 120
r
G 100
3394
3489
Kernels per row and kernel row response to plant
population, 5 locations.
48
44
40
36
32
28
24
20
16
12
kernels/row
rows of kernels/ear
9
18 27 36 45 54 63 72 81 90
Plant Population (x 1000)
Paszkiewicz et al., 2003
GDU silk, shed and anthesis-silking interval
response to plant population , 5 locations.
1400
GDU Shed
1375
GDU Silk
s
1350
'
U 1325
D
G 1300
ASI
50
25
0
1275
ASI – negative number indicates that
silks exserted prior to shed.
1250
9
18 27 36 45 54 63 72 81 90
Plant Population (x 1000)
Paszkiewicz et al., 2003
-25
A
S
I
Thank You!!!