Relationship between Seed Yield and Dry Matter Production in Unbranched Soybean ‘Fukuyutaka’ and ‘Misato-zairai’ Shaded from Flowering

Abstract

We analyzed the seed production of soybean (Glycine max (L.) Merr.) plants growth of cultivars 'Fukuyutaka,' popular in western Japan, and 'Misato-zairai,' local to Mie Prefecture, grown under shade from beginning bloom (R1) stage. To simplify the sink-source relationship, all branches and buds were removed during the shading. In both cultivars, shading decreased pod and seed numbers and seed weight. These were correlated linearly with pod growth rate after flowering, except that the relationship with seed weight was quadratic. Shading also decreased total dry weight, but had little effect on leaf area index (LAI) or SPAD at the beginning seed stage (R5). Pod growth rate after flowering was correlated with crop growth rate (CGR) during pod set. CGR was corelated with net assimilation rate (NAR), but not average LAI during pod set. Stem weight at maturity was corelated with LAI at R5. 'Misato-zairai' responded to shading similarly to 'Fukuyutaka,' but with large increases in CGR with NAR and in stem weight with LAI at R5.

Effect of Nitrogen Fertilization and Inoculation with Bradyrhizobium japonicum on Nodulation and Yielding of Soybean

“…It can also result from the effect of plant shading, which causes a decrease in the number of pods and the number and weight of seeds per plant [64]. In this experiment, an increase in LAI values in the R2-R4 phases was observed, and not only a tendency of a decrease in the number of pods per plant, but an increase in the number and weight of seeds from the plant and the weight of 1000 seeds was also observed.…”