The Effect of the Day Length and Temperature on the Flowering and Growth of the Early Soybean Varieties (Prelimnary report)

Abstract

Examining the effect of day length (13 and 15 hours) and temperature (low-average 18.4°C and high-average 21.2°C) on the flowering and growth of soybean varieties of Hokkaido and Kyushu, we got the following results. 1. The extreme early varieties of Hokkaido were low in response to the short day length than the extreme early varieties of Kyushu. In most varieties flowering is promoted more or less with high temperature, but Hokkaido varieties are sensitive, particularly under 15 hrs. day length flowering is delayed. 2. The number of node of their main stem was slightly influenced by temperature. but it was conspicuously increased by high temperature in Hokkaido varieties. Besides, it was increased by long day length, but in Hokkaido varieties it was slightly increased under low temperature.