Abstract
“Sachiyutaka” was recommended as a cultivar to be grown by Yamaguchi Prefecture in 2001. It is usually sown in mid-June but sometimes in July, because rain disturbs the sowing during the rainy season in June and July. We investigated the effect of later sowing, early July, on its yield and yield components. In addition, we confirmed the higher seed yield of “Sachiyutaka” than the other conventional cultivars in both standard and later sowing. “Sachiyutaka” sown in early July did not show lower seed yield than that sown in mid-June because of heavier seed weight and higher harvest index even though it had fewer ripening pods and lighter biomass. The average temperature during the seed ripening period was lower in the plants sown in early July than in mid-June. Not only ripening pod number but also seed number per pod and seed weight showed a significant positive correlation with seed yield in the plants sown in mid-June and in early July. “Sachiyutaka”
