小麦

In this experiment, the author s elected 8 wheat varieties, considering their winter habit and age of origin. They were distributed in 1929 from Konosu main wheat breeding center to central or local wheat breeding center when the organized wheat breeding system was started. In 1939, 52 samples of those varieties were gathered from 13 localities in Japan proper, Korea and Manchuria. Therefore they had settled just 10 years in their delivered stations till this experiment was started. Progeny tests were continued during 5 generations, selecting individuals which showed the earliest and the latest date of earing out of local strains composing 2-6 lines. Comparing the degree of variation s among local strains or intra-local strain lines on such characteristics as date of shooting, length of culm and panicle, number of panicle per plant, length and width of flag-leaf, length of peduncle, weight of 1,000 grains and phenol reaction of grain, he roughly classified tested varieties into three categories, that is, comparatively stable type, diverging type and differentiated type. Generally speaking, newly established varieties belong to the first type and old varieties tend to belong to the third type. From other view point, variations were divided into two dimensions, namely, macro and micro variations. The former was preferably considered as an off-type of the original stocks and the latter appeared universally among local strains or intra-strain lines. The macro variations were usually discovered in the farmost delivered materials. He also confirmed by statistical analysis of variance that there were recognized highly significant differences among total lines, between locality and among intra-strain lines of such characteristics as date of shooting, length of culm, number of panicles for some varieties. From this experiment he concluded that almost all of the wheat varieties tested continued to break down or differentiate into new ecotype adapting their genetic constitution to new habitat during ten years.