Studies On Relationship Between Agronomic Traits And Yield In Different Soybean Types

To study the relationship between main agronomic traits and yield of different ecological type of soybeans,cluster analysis was carried out on the 18 registered materials,and then comprehensive evaluation was analyzed by using the method of gray correlation degree and correlation analysis.The results as follows:1.The 18 varieties,was divided into 6 categories with cluster analysis in the Euclidean distance at OD=5.54:the first kind was the multiple branch of sub limited pod;the second was multiple branch of limited pod;the third was the medium branch of limited pod;the fourth was medium branch of sub limited pod;the fifth was few branch with Lanceolate leaf and elliptical leaf;the sixth was multi branched indeterminate type.2.The correlation of production and the major agronomic traits was as follows:three pods length(r=0.76374)>three pods width(r=0.76059)>two pods width(r=0.76017)>seed number per pod(r=0.7438)>stem weight(r=0.73498)>two pods length(r=0.71345)>grain number(r=0.71216)>number of branchs(r=0.70915)>total grain number(r=0.70792)>total pods number(r=0.8031)>bottom pod height(r=0.70767)>100 seed weight>plant height>stem diameter>one pod weight per plant>three pods weight per plant>seed weight per plant>node number>two pods weight per plant>four pods weight per plant>Weight of pods and grains>flat pods.The agronomic traits of three pods length?three pods width?two pods length?two pods width?seed number per pod had a great effect on yield,especially increasing three pods weight per plant and the ratio of pods per pod would be of great help for the high yield under the drought condition.Soybean Germplasm with multiple branches,stem weight and grain weight also had a great potential of production increase.Compared with other agronomic traits,such as grain weight per plant and plant height had little effect on the yield.3.Under the grought condition,the yield had significant positive correlation with the number of branchs(r=0.535*)?seeds weight per piant(r=0.787**)?the mumber of two and three pods(r=0.591and r=0.540*)?weight of pods and grains(=0.697**)?numbe of total pods and seeds(r=0.641**)?seeds weight(r=0.699**)?and Stalk weight(r=0.742**).4.The highest yield value was different with the different density and different soybean branch type.Under the special drought conditions,the yield of the multiple branch type had a "rising-droping-rising" tendency with the increase of density,peak up at the density of 240 thousand per hectare.With the increase of density,the yield of medium branch type showed a droping-rising-droping tendency,and it presented two peak values at the density of 120 thousand plants per hectare and 210 thousand plants per hectare,respectively,and the maximum yield was at the point of 120 thousand plants per hectare.,The few branch yield of the lance leaf and the oval leaf type showed a droping-rising-droping tendency with the increase of density.The yield reached to the peak when the density was 150 thousand plants per hectare for the oval leaf type,while it was 180 thousand plants per hectare for the lance leaf type.The variation tendency of the total grain number of three types was consistent with the total pod number with the increase of density.