Effects of rainfall, temperature and illumination on outcrossing rate of male sterile line in soybean

To improve seed yield of male sterile line, the relationship between outcrossing rate and climate factors was explored. Data of blooming period, outcrossing rate of male sterile line and climate during 2006–2016 growing seasons were investigated and analyzed. The shortest blooming period was 18.8 ​d with mean temperature of 24oC–25 ​°C and 18.5 ​d with about 125 ​h natural illumination. More rainfall caused a longer blooming period, and a high outcrossing rate was found with about 100 ​mm rainfall and the mean temperature of 24oC–25 ​°C. Increased natural illumination time by tapetum lucidum mulching improved outcrossing rate by 42.48% compared tocontrol. Overall, the selective combination of climate and environmental factors could be effective for increasing outcrossing rate and hybrid seed yield in the male sterile line of soybean.