Analysis of diversity among cytoplasmic male sterile sources and their utilization in developing F1 hybrids in Pearl millet [Pennisetum glaucum (R.) Br] C. Tara Satyavathi*, Sakkira Begum, B. B. Singh, K. V. Unnikrishnan and C. Bharadwaj
Division of Genetics, Indian Agricultural Research Institute, New Delhi 110 012
Abstract The present study aims at analysis of diversity among parental lines of different cytoplasmic sources and their utilization in developing F1 hybrids. Seven male sterile cytoplasmic lines belonging to A1 – 3; A4 – 2 and A5 – 2 were crossed with three elite restorers. The cluster analysis done with molecular data obtained from genomic DNA using SSR markers grouped the parental lines belonging to A1 cytoplasm into one cluster, A4 into one and A5 into the other. The assessment of the performance of the F1 hybrids was done through standard heterosis, heterobeltiosis and economic heterosis. The study clearly indicated that all the seven cytoplasmic male sterile lines coming from different cytoplasmic sources are capable of producing new superior hybrids. Physiological characters like chlorophyll, relative carotenoids and root length density have also been studied to assess the performance of parents and F1 hybrids. Higher economic heterosis was observed for yield in A 1 cytoplasm compared to A4 and A5 cytoplasms. Desirable effects of earliness and maturity can be obtained using A4 cytoplasm while desirable heterosis could be obtained for plant height, spike girth, number of nodes, chlorophyll content, relative carotenoids and 1000 grain weight from A5 cytoplasm.
an area of 9.33 m ha with a production of 8.15 m t and productivity of 882 kg/ha (2005-07). Pearl millet is a highly cross-pollinated crop. It exhibits tremendous amount of diversity at both phenotypic and genotypic levels . Genetic diversity in the species is distributed both within and among cultivars. Within-cultivar diversity can be very limited in case of single-cross hybrids, but is substantially greater in landraces and improved open-pollinated varieties of pearl millet. Estimation of genetic diversity and identification of superior genotypes are some of the basic objectives of any crop improvement programme. Highly diverse genotypes can be utilized as parents in hybridization programmes to produce superior hybrids/varieties. Thus, there is a need to evaluate available genotypes for the extent of genetic diversity. DNA markers have been used to evaluate genetic diversity in different crop species . Various molecular markers are being used for diversity estimation such as restriction fragment length polymorphisms (RFLP), random amplified polymorphic DNA (RAPD), micro satellites and amplified fragment length polymorphism (AFLP). Microsatellites have proven informative to study genetic relationships among closely related plant species as well as among sub-populations because of their exceptionally high level of polymorphism. The development of SSR markers in pearl millet is viewed as a major milestone in providing pearl millet geneticists and breeders with user-friendly and higher efficient molecular markers for exploitation in trait analysis, marker assisted breeding and variety identification. Qi et al.  identified several SSRs in pearl millet and grouped them into different linkage groups.
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Pearl millet, cytoplasmic male sterility, diversity, SSR, heterosis
Introduction Pearl millet is the staple food and fodder crop of millions of poor people living on the most marginal agricultural lands of Africa and Indian subcontinent. It is the only cereal that can be grown under dry land conditions and indeed in some of the hottest and driest regions where no other crop can be grown and thus plays a critical role in food security. In India,...