A statistical analysis of yield factors in soybeans

1. By analysis of variance it was demonstrated that the 237 strains of soybeans under study differed significantly in height of plant, number of nodes per plant, number of pods per node, number of seeds per pod, percentage of abortive seeds, weight of 100 seeds, and yield. 2. The characters height of plant, number of pods per node, size of seeds, and yield were greatly influenced by soil differences. Number of nodes per plant was less influenced by soil differences and the number of seeds per pod and percentage of abortive seeds were very little influenced by soil differences. 3. Significant simple correlations were found between yield and height of plant, number of nodes per plant, number of pods per plant, and number of pods per node. 4. Seed size was positively correlated with percentage of abortive seeds and negatively correlated with height of plant, number of nodes, number of pods per node, and number of pods. This indicates that there is probably a physiological relationship involved which would make combining large seed size with desirable expressions of these other characters very difficult. 5. A multiple correlation coefficient of 0.5822 was found between yield and its estimate from the complex of factors height, number of nodes, number of pods, percentage of abortive seeds, and the weight of 100 seeds. 6. Significant partial regression coefficients were given by height, pods, and weight of 100 seeds. The other factors gave very small partial regression coefficients indicating that they contribute very little information concerning yield not already given by the first mentioned factors. 7. Seventeen per cent of the variation in yield between strains was accounted for by its regression on the factors height of plant, number of pods per plant, number of nodes per plant, percentage of abortive seeds, and seed size. 8. Height of plant and number of pods per plant were the most important characteristics in estimating yield.