2025 Volume 94 Issue 3 Pages 209-218
A high steely grain rate lowers the quality of hulless barley. However, the mechanism of the occurrence of steely grain is not clear. In this study, we investigated the occurrence of steely grains in each tiller and each spikelet position and analyzed the related causes. Steely grains occurred more frequently at higher nodal tillers and lower spikelet position. Interestingly, the steely grain rate was correlated positively with the flowering date. Therefore, the difference in the steely grain rate among tillers is attributed to the variation in flowering date. The steely grain rate markedly decreased during the later ripening stage at the same time as rainfall. Also, by soaking in water the grains that had a moisture rate under 22%, the steely rate decreased, which suggested that water absorption of grains by rainfall was involved in the decrease. On the other hand, the steely grain rate did not decrease when the grains with more than 30% moisture were soaked. The period from flowering to rainfall was shorter for the grains at the higher nodal tillers and the steely grain rate was not decreased by soaking because of the high water content of the grains. In addition, it was considered that the grains in the lower position of the panicle had a higher water content than those in the higher position at 35 to 40 days after flowering, resulting in the frequent occurrence of steely grains.
