Development of doubled haploids from an elite indica rice hybrid (BS6444G) using anther culture

A total of 200 doubled haploids (DHs) were generated from an elite rice hybrid, ‘BS6444G’ for which an androgenic method was developed by manipulating the physical and chemical factors. The spike pretreated at 10 °C for 7–8 days was effective for callusing and green plant regeneration. The maximum callus frequency was achieved when the anthers cultured in N6 medium supplemented with 2.0 mg L−1 2,4-diclorophenoxyacetic acid, 0.5 mg L−1 6-benzylaminopurine and 3% maltose. Calli induced in N6 media also showed significant green shoot regeneration in MS medium supplemented with 0.5 mg L−1 1-napthalene acetic acid, 0.5 mg L−1 kinetin, 1.5 mg L−1 benzylaminopurine and 3% sucrose producing 210 green plants. Assessment of the ploidy status showed 95.71% fertile diploids and 4.2% polyploids; no haploids were observed. A total of 38 sequence-tagged microsatellite (STMS) markers proved able to discriminate a heterozygote from all the 200 DHs. The DHs grown in the field showed significant variation for their agronomic traits. Comparison of traits with control indicates homogeneity within each DH line and significant variance of traits between DH lines. Nine DH lines produce higher grain yield than the hybrid parent which suggests the possibility of exploiting hybrid vigor in indica rice through the development of DH lines of high yielding hybrids.