作物の生育・収量に及ぼす栽植の不均一性の影響に関する研究 : 第1報 1株植付苗数の不均一性が水稲の生育・収量に及ぼす影響

抄録

In order to examine the effect of nonunifomity of seedling number per hill on the growth, yield and yield components, seven kinds of rice populations were set; A)uniform populations which consist of the hills of the same number of seedlings, 1. all one seedling hills (1-1), 2.all three seedlings hills (3-3), 3. all six seedlings hills (6-6), B) nonuniform populations which consist of the hills of the different number of seedlings, 4. one and three seedlings hills alternately (1-3), 5. three and six seedlings hills alternately (3-6), 6. one and six seedlings hills alternately (1-6), 7. one, three and six seedlings hills alternately (l-3-6). The results of the study were as follows. 1. Differences in tiller number and top fresh and dry weight were observed among treated populations at the beginning of growing period, however, ultimately significant differences could not be observed. 2. In nonuniform population, each hill showed interaction and mutual compensation among one another. For an example, in the nonuniform population, 1-6, six seedlings hill depressed the growth of one seedling hill and reversely one seedling hill promoted the growth of six seedlings hill, compared to those in uniform one or six seedlings population, 1-1, or 6-6. These mutual effect was almost equal, so the growth of the nonuniform population, 1-6, as a whole, was almost same as the average of the growth of two uniform populations, 1-1 and 6-6. Accordingly the growth decrease caused by nonuniformity could not be observed over the growing period. 3. The growth variabilities among each hill in the nonuniform populations remained to.be greater than those in the uniforrn populations over the growing period. 4. These tendencies found in growth refLected to yield, so, yield decrease by nonuniformity could not be observed.