Breeding for Male-Sterility Line with G. barbadense Nuclear Background and Cytological Observation of Its Microsporogenesis

To study the feasibility of utilizing the heterosis of interspecific (Gossypium barbadense × G. hirsutum) hybrid cotton based on cytoplasmic male-sterility system, a G. barbadense male-sterility line HaiA with G. harknessii cytoplasm and its maintainer HaiB were developed by replacing nuclear genome from G. hirsutum to G. barbadense in a backcross breeding program. Its male cell abortion was observed using a light microscope through a paraffin slice for H.E staining technique. The results showed that the abortion characteristics in HaiA were not significantly changed at the cytological level, although G. hirsutum nuclear genome of sterile line was replaced by G. barbadense nuclear genome, and its abortion mainly took place at the stage of the microspore mother cell meiosis. HaiA sterility was very stable because of its early abortion and no-poltens in anthers. Hybrids between HaiA and G. hirsutum restorers were high in pollen viability, boll setting rate, boll weight and lint percentage which contributed to high yield heterosis. It is suggested that HaiA is of great value in the application of cotton interspecific hybrid seed production.