| The finding of cytoplasmic-nucleic male sterility, "three–line hybrid" and photoperiod- sensitive in soybean,that made the utilization of soybean heterosis become possible.But there were much difficulty in the male-sterile line production and how to select who were parent of the cross combination , the key to lowly in percentage of cross pollination was that the petal were too small and too much,the pollen grain were little wet and heavily , the pistil and stigma were tightly encased by the wing and keel petal,anther and stigma were not exserting , it was difficult to open pollination by insect or wind,and the petal and pod fell too easily,so the key to restrict heterosis were the bloming and pollination .To study genetic variation of floral character which influence outcrossing , and relationship between it and agricultural character will provide scientific basis for parent and germplasm source selection in new cultivars breeding .The correlation and stepwise regression , using the average of two year experiment data , of seven floral characters and three yield component in one hundred and sixty-six Henan soybean cultivated variety were studied to analysis the correlation between floral characters and yield component , provides the theory basis for the soybean breeding in yield level breakthrough.The results revealed that :floral characters had significant correlation at the level of 5% or 1% each other , and so were the partial floral characters to the yield component.From that,the flower sepal , the calyx lobe length and the length of the petal coming out the sepal had relatively greater influence to 100-seed weight and seed weight per plant than other floral characters .The stepwise regression analysis of other floral characters to stigma showed that the caylx lobe length , the length of the petal coming out the sepal and the style length had great correlation to stigma .The correlation of heritability , phenotype and enviroment of main floral character have been studied in 32 cultivated soybean . The results showed that the broad-sense heritability of most floral characters was high , except for synsepal length , among genotype variation coefficients , the length of the petal coming out sepal , synsepal length and stigma length were much higher than other floral characters , so was the genetic advance ; the genetic correlation coefficient showed a non-significant correlation between floral and other agronomic characters but the 100- seed weight and seed weight per plant ; there have a high correlation between the curved sepal length , the length of the petal coming out sepal and seed weight per plant,and between sepal length , the calyx lobe length , petal length , the length of the petal coming out sepal , pollen grain diameter and 100-seed weight ; in addition , there was a significant negative correlation between pistil length and the number of inefficient branching in cultivated soybean.Floral traits and cluster analysis of 90 soybean varieties from cultivated variety , semi-cultivated and wild soybean were conducted . The results showed that the genetic coefficient of each floral character was wild soybean≥semi-cultivated soybean≥cultivated soybean ,except the length of the petal coming out sepal and stigma length and stigma length .in all , there were a low level of genetic variation in most floral character of the three type of soybean , but the length of the petal coming out sepal . pollen grain diameter was the smallest .By the cluster analysis the material was classified into 3 groups when the threshold was 4.00 .Each group had obvious features,so it would be helpful to acquire highly heterotic combinations by distant and different orign varieties,and improve parent selection efficiency in highly heterotic breeding .
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