On the Occurrence of White Core, Milk-White Grain, and White Belly in Rice Plant

[摘要] Following tests were made in order to study the effects of restriction or encouragement of nutrient locomotion into kernels on the occurrence of white core (Shimpaku), milk-white grain (Nyuhaku-mai) and white belly (Haraziro) in rice plant: 1) The boot-leaf or upper half of a panicle was cut off at various stages after heading. 2) Rice plants were kept under darkness for 4 days at various stages after heading. The results were summarized as follows: 1. White core: The first test had no effect on the occurrence of white core. But, in the second test, white cores were numerously found in the panicles which had been under darkness at 5 to 14 days sfte heading.(Fig.2) Rice kernels began to become translucent from the core at 7 or 8 days after flowering under normal condition. By checking the nutrient locomotion into kernels for a few days at that time, letting the core of kernel remain as opaque, and letting the outer part of kernel become translucent, the karnel would become recognized as white core. 2. Milk-white grain: In the sdcond test, milk-white grains occurred numerously in the panicles treated at 10 to 15 days after heading.(Fig.2) The opaque part of the milk-white grain was a little outer than the white core. 3. White belly: In the first test, white bellys increased remarkably by cutting off the leaf at 10 to 15 days after heading(Fig.5.D), and decreased by cutting off upper half of panicle at heading time(E), or cutting off the leaf at heading time and upper half of panicle at 10 to 15 days afte heading(C). In the second test, white bellys occurred numerously in the panicles treated at 19 to 24 days after heading.(Fig.2)

[学科分类] 农业科学（综合）