Genetic and Environmental Variation of First Pod Height in Soybean [Glycine max (L.) Merr.]

First pod height (FPH) is an agronomic trait for the mechanical harvesting of soybeans with combines. The seed loss could be minimized, if the FPH is higher than the height of the cutter bar in combines. Hence, developing soybeans with high FPH has become one of important breeding goals in current crop improvement programs. The objective of this study was to evaluate genetic and environmental variation of FPH in soybean and to analyze the effect of ratio of FPH to plant height (PH) on seed yield. Four genotypes were evaluated across six different environments to analyze environmental variation of agronomic traits including FPH. Three F2 populations were evaluated to analyze genetic variation and relationship between the ratio of FPH to PH and seed yield. The main effects of planting distance, genotype and seeding date were significant for FPH, but FPH is affected more by genetic factors than by environmental factors. The mean heritability value of FPH was 66% across three F2 populations. Seed yield was found to reduce with increase in the FPH/PH ratio. In conclusion, genetic factors have effect more than environments to the variation of FPH. While FPH is higher than cutting height, the smaller ratio can minimize seed yield decrease.