Presentacion de 11th Asian Maize Conference which took place in Beijing, China from November 7 – 11, 2011.

1. Yield gains and agronomic traits of
maize varieties released in China
during the past six decades
Shihuang Zhang, Xiaoke Ci, Mingshu Li, Jiashun
Xu, Degui Zhang, Xiaoling Liang (CAAS, Beijing,
China)
xkc-99@yahoo.com.cn
Maize Center, ISC, CAAS
Chinese Academy of Agricultural Sciences

2. Maize yield
12.0
America Argentina China
Vietnam Myanmar
10.0
8.0
6.0
4.0 y=107x+974
y=38x+4586
2.0
0.0
61
63
65
67
69
71
73
75
77
79
81
83
85
87
89
91
93
95
97
99
01
03
05
07
09
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
20
20
20
20
20
Years
Data from FAO
Chinese Academy of Agricultural Sciences

3. • Problems in maize breeding
• Strategies for more effective breeding
The research since 2005
Chinese Academy of Agricultural Sciences

4. materials
1950s：Golden queen, Xiaolihong, Yinglizi, Baimaya
1960s：Sishuang 1，HD409， Weier156，US13
1970s：Xindan 1, Zhongdan 2, Zhengdan2, Qundan105,
Jidan101
1980s：Yedan 4, Huang417, Shendan 7，Danyu13，Yedan 2,
Nongda60, Tiedan 4
1990s：Benyu 9, Yedan13, Sidan19, Zhengdan14，Yedan19,
Jidan159, Nongda3138, Nongda108, Ludan50, Jidan180
2000s：Zhengdan958，Xianyu335，Shendan16，Ludan981,
Denghai 9
Chinese Academy of Agricultural Sciences

5. design
• The trial design was a randomized complete
block in a split plot arrangement with
density as main plot and hybrid as subplot.
• Subplots consisted of two rows 0.6 m apart
and 4 m long.
Chinese Academy of Agricultural Sciences

6. Year Densities
30 000 plants/ha
2005-2006 45 000 plants/ha
60 000 plants/ha
15 000 plants/ha
2007-2009 45 000 plants/ha
75 000 plants/ha
Chinese Academy of Agricultural Sciences

7. Locations
Urumchi
Shenyang
Beijing
Xinxiang
Sanya
Chinese Academy of Agricultural Sciences

8. Objectives
Ⅰ yield gains and its association with
plant densities
Ⅱ agronomic trait changes accompanied
with yield
Ⅲ N utilization and its association with
released decade and stay-green
provide a basis for designing more
effective future breeding strategies
Chinese Academy of Agricultural Sciences

9. I. Yield gain and its association
with plant densities
i Genetic yield gain
ii Tolerance to stress
Chinese Academy of Agricultural Sciences

10. 1. Genetic contribution to total yield gains
from 1970-2000
12.00
Total yield gain
Yield of the 2000s hybrids at 75 000 plants/ha
Gengtic yield gain
10.00 C
8.00
Yield of the 1950s OPVs at 75 000 plants/ha
CD – breeding
contribution
B
6.00 53%
4.00
A
2.00 Yield of the 1950s OPVs at 15 000 plants/ha
0.00
1940 1950 1960 1970 1980 1990 2000 2010
Year The method from Tollenaar (2002)
Ci et al. Euphytica, accepted
Open pollination varieties (OPVs)
Chinese Academy of Agricultural Sciences

11. ⅰ Genetic yield gain
ⅱ Tolerance to stress

12. 1. Tolerance to stress
Yield at different densities
12.0
15 000
45 000
10.0 75 000 y = 0.11 x - 205.03
R2 = 0.97
8.0
y = 0.09 x - 177.52
R2 = 0.95
6.0
4.0 y = 0.06 x - 111.74
R2 = 0.91
2.0
0.0
1940 1950 1960 1970 1980 1990 2000 2010
Year
Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Sciences

13. • Yield gain increased significantly with increasing
plant densities.
New hybrids have more tolerance to stress from
the 1950S to 2000S. (Here, Tolerance to stress includes
high densities, diseases, insects and so on)
Chinese Academy of Agricultural Sciences

14. 2. Tolerance to high densities
Yield in Urumchi
16.0 16.00
30 000 15 000
y = 0.084x - 156 45 000
45 000 14.00
14.0 R2 = 0.71 75 000 y = 0.040x - 66
60 000
R2 = 0.344
12.00
12.0
y = 0.124 x - 236
R2 = 0.91 10.00 y = 0.049x - 87
10.0 R2 = 0.5924
8.00
8.0
y = 0.103x - 196 6.00 y = 0.046x - 84
R2 = 0.91 R2 = 0.7079
6.0 4.00
4.0 2.00
1960 1970 1980 1990 2000 2010 1960 1970 1980 1990 2000 2010
Year
Ci et al. Crop Science, 2010
Chinese Academy of Agricultural Sciences

15. 30 000： y = 0.103x - 196 r = 0.96 15 000： y = 0.046x - 84 r = 0.84
45 000： y = 0.124x - 236 r = 0.95 45 000： y = 0.049x - 87 r = 0.77
60 000： y = 0.084x - 156 r = 0.84 75 000： y = 0.040x - 66 r = 0.58
No significant difference between regression
coefficient at different densities.
Hybrids improved slightly in tolerance to high densities.
Hybrids did not attain greater tolerance to higher densities of
60,000 to 75,000 plants/ha as yet in China.
Ci et al. Crop Science, 2010
Chinese Academy of Agricultural Sciencesc

16. 3. The Contribution of Stress Tolerance
Locations Environment Genetic yield gain
Beijing a typical environment  increased efficiency in
with serious biotic and grain production
abiotic stress  improved tolerance to
stress
 increased efficiency in
abundant sunshine and grain production
Urumchi few diseases and insects  improved tolerance to
High densities
Chinese Academy of Agricultural Sciences

17. compare
Beijing Xinjiang
30 000 plants ha-1 ： y = 0.064x - 121 y = 0.103x – 196
45 000 plants ha-1 ： y = 0.116x - 222 y = 0.124x - 236
60 000 plants ha-1 ： y = 0.155x - 301 y = 0.084x - 156
The contribution of stress-tolerance to genetic
yield gains was 46% at 60,000 plants/ha based on
the difference of regression coefficient between
Beijing and Urumchi
Ci et al. Crop Science, 2010
Chinese Academy of Agricultural Sciences

18. Compare
Beijing Xinjiang
15 000 plants ha-1 ： y = 0.041x – 75 y = 0.046x – 84
45 000 plants ha-1 ： y = 0.119x – 226 y = 0.049x – 87
75 000 plants ha-1 ： y = 0.151x - 288 y = 0.040x - 66
The contribution of stress tolerance to genetic
yield gains was 74% at 75,000 plants/ha
Ci et al. Crop Science, 2010
Chinese Academy of Agricultural Sciences

19. Summary
• With increasing plant densities, the contribution of
stress tolerance to total yield gain increased. Yield
improvement has occurred at a slow pace at densities
of 60,000 and 75,000 plants/ha in China.
• Further increasing maize yield will be achieved
through higher plant populations, and this will require
breeding for greater stress tolerance.
Chinese Academy of Agricultural Sciences

20. Ⅱ Agronomic trait changes
accompanied with yield
ⅰ Plant traits
ⅱ Ear traits
Chinese Academy of Agricultural Sciences

21. 260 120
255
115
250
110
Plant height (cm)
Ear height (cm)
245
240 105
y = 0.85x + 105
235 R2 = 0.07
y = 3.0x + 232 100
230 R2 = 0.48
95
225
Plant height Ear height
220 90
1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000
Year of release
(11 environments, 2007-2009) Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Science

22. 74 77
73 76
72 75
74
71
y = 0.74x + 68 73
Days
70 R2 = 0.47 y = 0.66x + 71
72 R2 = 0.39
69
71
68
70
67
69
66 Days to anthsis 68 Days to silking
65 线性 (Days to 67 线性 (Days to
1950 1960 1970 1980 anthsis) 2000
1990 1950 1960 1970 1980 1990
silking) 2000
Year of release
(11 environments , 2007-2009) Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Science

23. 10000
9000
)
2
Leaf area per plant (cm
8000
larger plant size and
7000
later maturity,especially
y = 443x + 5526
from the 1980s
6000 R2 = 0.78
5000
Leaf area per plant
4000
1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009) Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Science

24. 50
49
48
Leaf angle
47
y = -0.76x + 50
R2 = 0.58
46
45
44
Leaf angle
43
1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009) Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Science

25. 5.0
15 000 y = -0.02x + 2.1 r=-0.31
4.5 45 000 y = -0.07x + 2.8 r=-0.64
★
75 000 y = -0.19x + 3.7 r =-0.85
4.0
3.5
3.0
2.5
2.0
1.5
ASI
1.0
1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009) Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Science

26. 41 25
40 20
39 y = 0.29x + 39 15
y = -0.8x + 20
R2 = 0.35 R2 = 0.33
38 10
37 5
Tassel length Tassel branch number
36 0
1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009) Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Science

27. 18.0 12.0
15 000 y = -0.50x + 4.8 r=-0.94★ ★ 15 000 y = -1.12x + 6.4 r=-0.84
★
16.0 ★★
45 000 y = -1.09x + 8.4 r=-0.72 45 000 y = -1.47x + 8.7 r=-0.92
10.0 ★
14.0 75 000 y = -1.72x + 14.0 r=-0.88★ 75 000 y = -0.96x + 7.2 r=-0.82
12.0 8.0
lodging (%)
10.0 root lodging 6.0
8.0
6.0 4.0 stalk lodging
4.0
2.0
2.0
0.0 0.0
1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009) Ci et al. Euphytica, accepted
Chinese Academy of Agricultural Science

28. Summary
• Earlier maturity, shorter plant stature and
more tolerance to root and stalk lodging
under high density will be required for
further yield improvement

29. ⅰ Plant traits
ⅱ Ear traits
Chinese Academy of Agricultural Science

30. 25 4.6
4.4
20
4.2
y = 0.75x + 16
15
R2 = 0.876
cm
y = 0.11x + 3.8
4.0
R2 = 0.83
10
3.8
5
3.6
Ear length Ear diameter
0 3.4
1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009)
Chinese Academy of Agricultural Science

31. 15.5 45
40
15 y = 0.25x + 14 35
R2 = 0.90
30 y = 1.3x + 32
14.5 R2 = 0.61
25
20
14
15
10
13.5
Row number per ear 5
Kernel number per row
13 0
1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009)
Chinese Academy of Agricultural Science

32. 40
35
In America
Kernel number per ear have no
Kernel weight (g)
30
increase. increased grain yield
y = 1.9x + 24
25
R2 = 0.88
was contributed to increased
20 kernel weight (Duvick 2005).
15
10 In China
kernel weight and kernel number
5
hundred kernel weight
per plant (larger ear size).
0
1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009)
Chinese Academy of Agricultural Science

33. 84
83.5
83
82.5
82 y = 0.19x + 82
R2 = 0.12
81.5
81
80.5
80 shelling percentage
Percentage barrenness
79.5
线性 (shelling
1950 1960 1970 1980 1990 2000
percentage)
Year of release
(11 environments , 2007-2009)
Chinese Academy of Agricultural Science

34. Grain yield per plant
250
200
Grain yield per plant (g)
grain yield per plant had
150 y = 23x + 82
R2 = 0.94 improved greatly, but
tolerance to high
100 densities had not. This
is opposite to that in the
United States (Tollenaar and
50 Lee, 2002; Duvick, 2005)
Yield per plant
0
1950 1960 1970 1980 1990 2000
Year of release
(11 environments , 2007-2009)
Chinese Academy of Agricultural Science

35. Summary
• Yield gain in China mainly was due to
yield improvement per plant. Plant and
ear traits mentioned also reflected this
case.
• Chinese maize yield improvement can
benefit from agronomic strategies at
higher densities.

36. Ⅲ N utilization and its
association with released
decade and stay-green
Chinese Academy of Agricultural Sciences

37. 1. N requirement for 100 kg grain production
(2010, Beijing)
Golden Queen ZD2
YD13
ZD958
(Yuan & Mi et al., unpublished data)
Chinese Academy of Agricultural Sciences

38. 2. N concentration of grain in Chinese maize hybrids
(2010, Beijing)
2010 Beijing
Golden Queen
Grain N concentration (g/kg)
ZD2
YD13
R2=0.4049 ZD958
Year of release
(Yuan & Mi et al., unpublished data)
Chinese Academy of Agricultural Sciences

39. 3. Stay-green degree
(2010, Beijing)
Yellow-type
Middle-type
Stay-green degree (%)
Stay-green
R2=0.464
Year of release
(Yuan & Mi et al., unpublished data)
Chinese Academy of Agricultural Sciences

40. 4. Contribution of leaf N to grain N In Chinese
maize hybrids released during the past 60ys
The control
(2010, Beijing)
Contribution of leaf N to grain N
Yellow Middle Stay-green
R2=0.5954
R2=0.1522
(%)
R2=0.0587
Stay-green (%)
(Yuan & Mi et al., unpublished data)
Chinese Academy of Agricultural Sciences

41. Summary
Newer hybrids improved in N efficiency,
But contribution of leaf N to grain N reduced
in newer hybrids because of increased stay-
green.

42. Chinese Academy of Agricultural Sciences