Abstract
Rice seedlings of each of several varieties all grown on an upland nursery and an irrigated nursery were transplanted on ill-drained paddy fields at 18 localities in Chiba Prefecture, the planting technique being followed equally through all localities, and the growing behaviors of those plants were investigated. The results obtained are as follows; 1) Generally speaking, the crops of rice from the upland seedlings were better than those from the irrigated seedlings, especially when planted on sandy ill-drained fields. 2) The increase, however, owed rather to the increase in the straw weight than to that in the ear number. In the ealier period of growing, the stem number and weight of dry matter of upland seeded plants were larger than those of lowland seeded ones, but after the period of young ear forming, the differences became small. Therefore the authors consider that one of the properties peculiar to upland seedlings is their ability of increasing the dry matter of the whole plant during its vegetetive growth and that only when the effect lasts till its ripening period, the crop of the grain will increase. 3) The top-leaf ratio in the upland seeded plant was larger than that in the irrigated ones till the young ear forming period, but the difference between them decreased after heading. Therefore the authors believe that the superiority of the upland seeded plant in dry matter producing ability is related to the promoted growth its Ieaves or some physiological function of them. 4) The weight of individual ear of the upland seeded plants was not proved heavier than that of the lowland seeded ones. Whether the fact depended on the increase in the ear number of the former or on its original properties was not clear.
