The morphology of the plant and ear is a preliminary selection characteristic in breeding new varieties of maize.As new maize cultivars were developed from the 1950s through the 2010s in China,most had changes in both...The morphology of the plant and ear is a preliminary selection characteristic in breeding new varieties of maize.As new maize cultivars were developed from the 1950s through the 2010s in China,most had changes in both plant and ear morphological characteristics that contributed substantially to maize yield gains.Over the seven decades,plant and ear height fluctuated with a small increase from the 1950s to 2000s,and then a decrease in the 2010s,while the ear ratio and internodes length below the ear decreased significantly.Leaf angles became significantly more upright,especially for the leaves above the ear,and the leaf area per plant improved markedly.Leaf orientation increased from the 1950s to the 2000s then decreased in the 2010s.Tassel size and the anthesis-silking interval were both reduced substantially.Ear diameter,kernel number,and kernel weight increased from the 1950 to the 2000s,then decreased in the 2010s under the same cultivation conditions.We found that modern maize hybrids have a lower plant height,ear height and ear ratio which increased lodging resistance,a more erect leaf which increased high-density planting tolerance,and smaller ears and kernels which facilitated rapid dehydration during late grain filling.These morphological selection criteria,which are suitable for mechanized operations,are proposed as the focus for future maize breeding.展开更多
To find the most suitable row spacing, a field experiment with the cultivar of Xichengshu 007 was conducted to investigate the effects of 5 different row spac- ing on changes of yield with planted density at 60 000 pl...To find the most suitable row spacing, a field experiment with the cultivar of Xichengshu 007 was conducted to investigate the effects of 5 different row spac- ing on changes of yield with planted density at 60 000 plant/hm2. The results showed that the highest yield of fresh root occurred with row spacing of 90 cm, and the lowest yield of fresh root was with row spacing of 75 cm. With the in- crease of row spacing, the yield of fresh root gradually increased, and reached highest yield when it planted the row spacing with 90 cm. However, as the row spacing expanded, the yield of fresh root declined. In a word, it can get a good harvest when set the row spacing of 90 cm in southwest.展开更多
The "farm question" has long baffled China's planners. Since 1979, when China began the reform and opening up process, the economy has developed rapidly, especially the secondary and tertiary sectors. By...The "farm question" has long baffled China's planners. Since 1979, when China began the reform and opening up process, the economy has developed rapidly, especially the secondary and tertiary sectors. By 2005, China's GDP was 18.2321 trillion yuan, nearly 30 times that in 1979. However, the primary sector has largely been left out of this growth with its proportion in GDP dropping from 25.6 percent in 1979 to 12.4 percent in 2005. Rural areas remain poor and living standards low. Past efforts to change the ...展开更多
基金the National Key Research and Development Program of China(2017YFD0300302 and 2017YFD0300804)the China Agriculture Research System of MOF and MARA(CARS-02-63)the Natural Science Foundation of Inner Mongolia,China(2020MS03053)。
文摘The morphology of the plant and ear is a preliminary selection characteristic in breeding new varieties of maize.As new maize cultivars were developed from the 1950s through the 2010s in China,most had changes in both plant and ear morphological characteristics that contributed substantially to maize yield gains.Over the seven decades,plant and ear height fluctuated with a small increase from the 1950s to 2000s,and then a decrease in the 2010s,while the ear ratio and internodes length below the ear decreased significantly.Leaf angles became significantly more upright,especially for the leaves above the ear,and the leaf area per plant improved markedly.Leaf orientation increased from the 1950s to the 2000s then decreased in the 2010s.Tassel size and the anthesis-silking interval were both reduced substantially.Ear diameter,kernel number,and kernel weight increased from the 1950 to the 2000s,then decreased in the 2010s under the same cultivation conditions.We found that modern maize hybrids have a lower plant height,ear height and ear ratio which increased lodging resistance,a more erect leaf which increased high-density planting tolerance,and smaller ears and kernels which facilitated rapid dehydration during late grain filling.These morphological selection criteria,which are suitable for mechanized operations,are proposed as the focus for future maize breeding.
基金Supported by Special Fund for Modern Agricultural Technology Construction(CARS-11-B-12,CARS-11-C-23)Special Fund for Agro-scientific Research in the Public Interest(201303106)National High-tech R&D Program(863 Program)(2012AA101204)~~
文摘To find the most suitable row spacing, a field experiment with the cultivar of Xichengshu 007 was conducted to investigate the effects of 5 different row spac- ing on changes of yield with planted density at 60 000 plant/hm2. The results showed that the highest yield of fresh root occurred with row spacing of 90 cm, and the lowest yield of fresh root was with row spacing of 75 cm. With the in- crease of row spacing, the yield of fresh root gradually increased, and reached highest yield when it planted the row spacing with 90 cm. However, as the row spacing expanded, the yield of fresh root declined. In a word, it can get a good harvest when set the row spacing of 90 cm in southwest.
文摘The "farm question" has long baffled China's planners. Since 1979, when China began the reform and opening up process, the economy has developed rapidly, especially the secondary and tertiary sectors. By 2005, China's GDP was 18.2321 trillion yuan, nearly 30 times that in 1979. However, the primary sector has largely been left out of this growth with its proportion in GDP dropping from 25.6 percent in 1979 to 12.4 percent in 2005. Rural areas remain poor and living standards low. Past efforts to change the ...
