Genetic diversity, Heterosis and combining ability studies involing diverse sources of cytoplamic genetic male sterility in pearl millet [Pennisetum glaucum (L.) R.Br.]
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Date
2008
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UAS, Dharwad
Abstract
A total of 105 germplasm lines were crossed with three diverse sources of cytoplamic
genetic male sterility viz., A1, A4 and A5 to identify the restorers and to characterize the
cytoplasmic difference based on restorations pattern on three sources of male sterility
systems. The study revealed that, out of 105 lines, 36 lines (34.28%) on A1, 63 lines (60%) on
A4 and 47 lines (44.76%) on A5 cytoplasm restored fertility. The seed set percent was high
and stable on A4 (>70%), where as <60% on A5 and A1 cytoplasm. Seed set per cent was
comparatively high in kharif than summer irrespective of cytoplasmic sources.
Genetic diversity among the lines tested, restorers+ maintainers (105), restorers (61)
and maintainers (44) revealed that, genetic diversity was adequate among the genotypes of all
the three genotypes which fell into 22 (restorers + maintainers),11 (maintainers) and 19
(restorers) clusters. D2 values were in general high in restorers group followed by combined
and maintainers group. Among the twelve quantitative characters studied the most important
traits contributing to the divergence was days to maturity in all the three groups. The traits
like productive tillers per plant grain yield per ear, peduncle length, grain yield per plant,
1000 seed weight were next in the order.
Information on heterosis and combining ability was sought through two sets of L x T
experiments (I-involving three diverse sources cytoplasm, II-A1 source only). In both the
experiments considerable heterosis was observed for grain yield and its components. The
heterosis for grain yield was largely due to ear length, ear girth, ear weight and seed weight
and most productive crosses figure out as most heterotic crosses and vice versa in both the
experiments. Combining ability revealed that, majority of the characters are under the control
of non-additive gene action and sca variance greater than gca variance on over all basis in
both the experiments. Present study revealed that heterotic hybrids could be obtained from
parents with any combination of gca (viz., H x H, H x L, L x H and L x L).
A study on the inheritance pattern of rust resistance in F2 crosses indicated that the
rust resistance is monogenic dominant genes governs the susceptibility.
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Genetics and Plant Breeding