High-yield Characteristics of Summer Sowing Soybean Varieties

[Objective] This study aimed to investigate the characteristics of high-yield soybean varieties.[Method] The agronomic traits of six high-yield soybean varieties and other 57 summer sowing ones were investigated from 2007 to 2010.[Result] The higher-yield summer sowing soybean varieties should have higher plants （R=0.551 6＊）,more effective pods （R=0.739 7＊）,more seeds per pod （R=0.318 9）,more flowers per plant （＞130）,higher pod setting rate （＞52％）,smaller ratio of aborted pods （＜40％）,longer tap roots （more than 20 cm） and lateral roots （more than 15 cm）,shorter bottom nodes （the length of six bottom nodes should be less than 25 cm）,lower center of gravity of the plant （＜40 cm）,greater stem dry weight,higher dry matter transformation rate and continuously increasing seed weight in late seed filling stage.The ideal growth stage model for summer sowing soybean was that the durations between adjacent stages of sowing,seedling emergence,flowering,seed setting and maturity stage were 5,29-33,29-33,32-36 d,respectively.[Conclusion] This pattern could not only satisfy the ecological conditions for double cropping system,but also balance the full development of vegetative and reproductive growth,promote the yield formation of summer sowing soybean.

Genetic Variation Analysis, Correlation Analysis and Principal Component Analysis on Agronomic Traits of Summer Sowing Soybean (Glycine max Merr.) in Huang-Huai-Hai Region

Genetic variation analysis, correlation analysis and principal component analysis were conducted to investigate the relationship between 12 yield-related agronomic traits of 87 summer sowing soybean eultivars in Huang-Huai-Hai region. According to the experimental results, effective branch number showed the maxi- mum variation coefficient and growth duration showed the minimum variation coefficient. The variation coefficient of bottom pod height, pod number per plant, grain number per plant, grain weight per plant and 100-grain weight of semi-determinate summer sowing soybean ranged between 18.38% -27.56. The variation coeffi- eient of plant height, bottom pod height, pod number per plant, grain number per plant and grain weight per plant of determinate summer sowing soybean ranged from 21.02% to 8.04%. In semi-determinate summer sowing soybean, yield showed extremely significantly positive correlation with grain number per pod, grain weight per plant and 100-grain weight, but extremely significantly negative correlation with effective branch number and significantly negative correlation with growth duration. In determinate summer sowing soybean, yidd showed extremely significantly positive correlation with stem diameter but significantly positive correlation with bottom pod height, while it showed no significant correlation with other agronomic traits. Principal component analysis of yield-rdated agronomic traits showed that cumulative contribution rates of the former four principal components to the variation of seml-determinate and determinate summer sowing soybean were 79.92% and 79.50%, respectively. Agronomic traits with the greatest variation should be selected first. Semi-determinate and determinate summer sowing soybean individu- als in Huang-Hnai-Hai region should be selected according to different podding habits. In addition, semi-determlnate soybean varieties with moderate plant height and growth duration, fewer effective branches, more grains per pod and greater 100-grain weight should be selected; determinate soybean varieties with thicker stem diameter, higher plant height and bottom pod height, more nodes on main stem, fewer grains per pod, more pods per plant and grains per plant should be selected.

Analysis on Heterosis and Combining Ability of Main Agronomic Characteristics in Huang-Huai-Hai Summer Soybean

With 10 elite soybean varieties from Huang-Huai-Hai Valleys as materials,25 hybridization combinations were compounded based on NC II,and the heterosis and combining ability for the major agronomic characters in summer soybean was studied.The results showed that heterosis of agronomic traits of soybean was ubiquity,and the average heterosis of all characters showed positive advantages.The advantage of seed weight per plant,number of seeds per plant and number of pods per plant were the highest,at 35.58%,34.23%and 31.47%,respectively,and thus made a great contribution to yield heterosis.The general combining ability of Hedou 19,Handou 6,Shanning 14 and Williams 82 was relatively higher in seed weight per plant,number of seeds per plant and number of pods per plant,and they are quality parents for designing strong hybridization combinations.There were significant differences in special combining ability(SCA)among parents for the same trait in different combinations.Some showed positive effect,and others showed negative effects.We should select the best combination according to breeding objective in selecting and matching special elite combinations.