Relationship between Yield and Yield Components in Multiple Leaflet Soybean .

Abstract

A group of 8 normal leaflet soybean varieties were crossed with a group of three multiple leaflet soybean lines to obtain 21 crosses plus 22 reciprocal crosses. Five more crosses were also made within the multiple leaflet group. Thus, altogether 48 F2-crosses were grown at Suwan Farm Research Station during August-December 1983 to study the relationship between leaflet number, yield and yield components. Leaflet index was found to correlate negatively with 100 seed weight indicated that increasing the number of soybean leaflets tended to reduce seed size. Yield had positive correlation with pods per plant and 100-seed weight. The latter trait was also found to correlate negatively with days to flowering. Plant height, lodging, days to flowering, and days to maturity displayed positive correlation between each other. Path-coefficient analyses revealed that number of pods per plant, and 100-seed weight had positive direct to yield, while days to flowering had negative direct effect. Although direct effect of leaflet index was very low and negative, multiple leaflet soybean tended to produce slightly lower yield than the normal type under the population density used in this study. Pods per plant and 100-seed weight exposed high direct and indirect effect to yield, revealed that these three traits should be considered together if a plant breeder desires to select high yield genotypes out of these crosses. Crosses having ‘Williams’ or ‘Clark 63’ as a parent tended to produce high yield and exhibited important yield components, especially large seed size.