楊子江三角洲地帶の水稻に關する研究 : 第5報 幼苗の形態に現われる〓稻及び〓稻の型別的差異

抄録

In the Yangtzekiang Delta of Central China there are two formal kinds of cultivated rice plants, Sheng-Doh and Kuang-Doh. The former is presumed to be originated in Indian rice plant type and is very early harvesting although it thrives so vigorously. The latter, on the contrary, is genetically included in Japanese rice plant type and usually harvested in late fall. Each form is distinguished from another by its plant habit, coloring, shape of grains, maturity etc. collectively, apart from the troublesome progeny test obtained from crossing between them. In some cases, however, above-mentioned characters are not sufficient for the items of distinction from both types due to presence of varietal diversity in Sheng-Doh form. Firstly, in this report it is explained that the young leaves length of seedlings is characteristic of Sheng-Doh, Kuang-Doh or other rice plant forms, respectively. That is, a most of Sheng-Doh and Indian varieties have the longer first, second and third leaves than those of Kuang Doh and Japanese varieties. And only a few Sheng-Doh varieties, which have been already pointed out as peculiar ones that, for instance, have closely resembled to Kuang-Doh form or been resistant against drought, possess the exceptionally shorter leaves than the normal. Secondly, as to the main stem node which develops the first tillar, we can recognize the rather distinct difference in the written forms. The first tillars of most Sheng-Doh, Japanese land rice and Indian varieties appear from the second of their stems, but, on the other hand, those of Kuang-Doh and Japanese water rice varieties usually develop from the third node. And some Sheng-Doh varieties, which have been known as peculiar characteristic ones regard to the morphological or physiological properties, have the same tendency of tillering to the Kuang-Doh form. Thus, the proper characters of rice seedlings, for instance, length of leaves and first tillering position, may be serviceable marks to distinguish the difference between Sheng-Doh and Kuang-Doh quickly and to find out the peculiar variety which may bave latent characters for any ecological conditions.