Temperature and photoperiod effects on sterility in a cytoplasmic male-sterile soybean

Manual cross-pollination to produce large quantities of hybrid soybean seed is difficult and time consuming. An environmentally stable sterility syste m is one of the necessary components to produce large quantities of hybrid seed. The objective of this study was to subject cytoplasmic male-sterile ( CMS) BC5F1 plants, from a cross of a Chinese Glycine mar wild-type soybean with a Chinese wild annual soybean G. soja (male parent) and controls, to a variety of different temperature and photoperiod treatments to test whethe r CMS is stable under various environmental conditions. Plants were grown i n growth chambers under controlled temperature, photoperiod, and irradiance regimes until pod set, and then they were transferred to a glasshouse unti l they matured. Plants were evaluated for time of anthesis after photoperio d induction (13 h light/11 h dark) and fertility or sterility. Anther squas h and pod set data showed that sterility of the CMS line was stable under a ll environmental conditions tested, whereas fertility-restored control plan ts remained fertile. Extreme environmental conditions led to delayed floral induction and/or stunted growth.