A Preliminary Study on the Critical-Daylength Evoking the Photoperiodic Sensitive Male Sterility of Rice and Their Responses to Other Environmental Factors Effect of post-flowering daylength on agronomic characters of soybean Ecological basis of larger wheat ear formation Effects of daylength and temperature on the spike differentiation of winter wheat Studies on the Photoperiodic Responses in Short-Day Plant Helianthus tubevotus