RESUMO
Sorghum is the important cereal crop around the world and hence understanding and utilizing the genetic variation in sorghum accessions are essential for improving the crop. A good understanding of genetic variability among the accessions will enable precision breeding. So profiling the genetic diversity of sorghum is imminent. In the present investigation, forty sorghum accessions consisting of sweet sorghum, grain sorghum, forage sorghum, mutant lines, maintainer lines, and restorer lines were screened for genetic diversity using quantitative traits. Observations were recorded on 14 quantitative traits, out of which 9 diverse traits contributing to maximum variability were selected for genetic diversity analysis. The principle component analysis revealed that the panicle width, stem girth, and leaf breadth contributed maximum towards divergence. By using hierarchical cluster analysis, the 40 accessions were grouped under 6 clusters. Cluster I contained maximum number of accessions and cluster VI contained the minimum. The maximum intercluster distance was observed between cluster VI and cluster IV. Cluster III had the highest mean value for hundred-seed weight and yield. Hence the selection of parents must be based on the wider intercluster distance and superior mean performance for yield and yield components. Thus in the present investigation quantitative data were able to reveal the existence of a wide genetic diversity among the sorghum accessions used providing scope for further genetic improvement.
RESUMO
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.
