Studies on the Late Season Culture of Pady Rice in Hokuriku District. : 1. On the differentiation of withering appearances.

Abstract

The withering caused by transplanting, especially in late culture in summer season when both temperature and light intensity are high, is a serious problem because it apts ot cause delay of growth rate and decrease in yield. The degrees of withering were remarkably affected by the differences of conditions such as plant age and nutritional conditions in seedling stage. The withering is less with upland seedlings and older seedlings as compared to low land plant, and younger one respectively. The less withered plants are characterized by high percentage in dry matter and high ratio of dry weight/plant height. Next, as regards of the total nitrogen content and the respiratory rate per dry matter, the authers found the tendency that the larger these values are, the more severe the withering within either of seedlings of two types. But, in spite of the higher values of these characters of the upland seedlings, the withering of upland seedlings was less than that of low land seedlings. Because the old upland seedlings are resistant to withering, capable of producing larger amount of fresh root and of producing larger amount of fresh roots and of producing greater dry matter after transplanting, the old upland seedlings are considered to be most adaptable for the late season culture of paddy rice in Hokuriku district.