Improvement of Soybean Hybridization Success Rate during Winter Nursing in Hainan Island

Abstract

To accelerate the soybean breeding progress and to broaden the genetic basis of new varieties, it is necessary to improve the hybrid seed-setting rate of soybean during winter nursing. Seven early-maturing soybean varieties from northeast China were selected in hybridization experiments with photoperiod treatments in Sanya, Hainan, China. Morphological traits, growth and development periods, floral organ characteristics and pollen fertility were observed or documented under long day(LD, 18 h) treatment and normal short day(NSD) conditions, respectively. At the same time, the effects of light treatment, emasculation of the female parent, and flower bud size on the hybridization were investigated. The results showed that under the NSD environment in Sanya, the flowering period and plant height shortened, the flower number and single floral weight decreased, the flower and its constituents became smaller, and the pollen sterility rate increased(P0.01) as compared with those under LD treatment(P0.01). Taking the plants with big flower bud under NSD as the female parent, and the plants under LD treatment as the male parent, we made the crosses and pollinated without emasculation, with the hybrid seed-setting rate of 64.36%, which is high enough for breeding purpose. According to the results, we propose the solution for improving the hybridization success rate of soybean in winter nursery.