Studies on Heterosis and Seed Production of Hybrid between Cytoplasmic Male Sterile Lines and Restoring Lines in Colored Cotton

Eight cotton hybrids (F_1) between cytoplasmic male sterile lines and restoring lines in brown cotton (Gossypium hirsutum L.) were made and revealed that they were very significantly improved in lint yield and quality. The yields of 6 hybrid combinations among them were increased by (6.78%)~(22.49%) over that of an inbred brown cultivar Zongxu 1 (CK_2), especially 3 combinations of them (S003A×Zheda-qianghui, Kang A×S012 and X008A×S013) with higher yield than white cotton hybrid CCRI 29 (CK_1). In the fiber quality, the fiber length of KangA×S012 and X008A×S013 combination was 28.4 mm and 29.0 mm, respectively, similarly to CCRI 29; the strength and fineness of brown cotton hybrid were also improved significantly when compared with CK_2. Fiber color can be used as an indicative trait in the hybrid seed production since the brown fiber gene is dominant. According to this principle, seeds of brown (or white) sterile line and white (or brown) restorer line were mixed and then sowed in the field of hybrid seed production. Comparison with the row sowing fashion (regular fashion), the mixed sowing fashion could not only increase hybrid seed yield, but also improve lint yield and quality of the sterility line.