Plant regeneration from sorghum anther cultures and field evaluation of progeny

Summary Embryogenic calli were obtained from a hybrid line of Sorghum bicolor (L.) Moench anthers with mid to late uninucleate pollen cultured in N₆ medium supplemented with 3.0% sucrose, 2.0 mg/1 2,4-D, 0.8% agar and incubated at 30°C, which was the optimum temperature. The regeneration of embryos was obtained from the embryogenic calli cultured in modified MS medium supplemented with 3.0% sucrose, 2.0 mg/1 BAP combined with 0.3 mg/1 IAA and 0.8% agar. A total of 248 doubled haploids and 12 haploid plants were regenerated. In a subsequent field study, the selfed progeny from anther culture (designated as the anther culture-2, A₂] generation) derived families was compared with both the F₂ and the F₁ for agronomic and morphological traits. Significant differences were noticed between the family means of both A₂ and F₂ for all the quantitative traits studied. The distinctive difference in the behavior of the A₂ families in comparison with the F₂ was established by within family variance, which was significant in F₂ for days to 50 per cent flowering, plant height, panicle length, leaf area index, dry matter production, harvest index and grain yield and was non-significant in A₂. Male sterility, one of the potentially important traits, currently exploited in the hybrid seed production of cereals, including CSH5 hybrid sorghum and the morphological traits (panicle shape, compactness, grain color, glume color and nature of the leaf sheath) segregated in the F₂. Such segregation was not observed within A₂ families and they bred true to their respective A₁ plants, indicating the rapid attainment of homozygosity/uniformity. The present study establishes the gametophytic origin of anther culture derived families and indicates the possibility of rapid production of homozygous lines which can be used as recombinant inbreds.Abbreviations N₆ Chu et al. (1975) - MS Murashige and Skoog (1962) - 2,4-D, 2 4-Dichlorophenoxyacetic acid - IAA Indole-3 -acetic acid - BAP Benzylaminopurine - A₁ regenerated plants - A2 selfed progeny from A₁