Heterosis in cms based hybrids of Pigeonpea [cajanus cajan (l.) Millsp.]
An investigation on heterosis in CMS based hybrids of pigeonpea [Cajanus cajan (L.) Millsp.] was carried out during kharif 2015 at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru with 24 hybrids and four checks to elicit the information on magnitude of the genetic variability, heritability, genetic advance as per cent of mean, character association, path coefficient analysis, extent of fertility restoration and heterosis. Observations were recorded on ten characters viz., days to 50% flowering, days to maturity, plant height (cm), number of primary branches per plant, number of secondary branches per plant, number of pods per plant, pod weight per plant, 100 seed weight (g), grain yield per plant (g) and mean pollen fertility %. Analysis of variance showed significant differences among the hybrids for all the characters studied indicating a high degree of variability in the experimental material. The genotypic coefficients of variation for all the characters studied were lesser than the phenotypic coefficients of variation indicating the influence of environment on expression of these traits. High genetic variability coupled with high heritability and genetic advance as per cent of mean were recorded for number of primary branches per plant, number of secondary branches per plant and pollen fertility % indicating the role of additive genes in governing the inheritance of these traits. The correlation study indicated that grain yield per plant was significantly associated with days to 50% flowering, days to maturity, number of primary branches, number of secondary branches, number of pods per plant and pod weight indicating their importance as selection criteria in pigeonpea yield improvement programmes. Path coefficient analysis revealed that pod weight per plant and number of primary branches had positive direct effects on seed yield per plant. Hence, these traits should be considered as important selection criteria in all yield improvement programmes and direct selection for these traits is recommended. Fertility restoration studies showed that 15 out of 24 hybrids recorded high (>80 %) pollen fertility and exhibited better fertility restoration. Nine out of 13 male lines showed fertility restoration of more than 80% and were classified as restorers for corresponding CMS lines. The present investigation also revealed high levels of heterosis i.e. over 50% in traits like number of pods per plant, pod weight per plant and grain yield per plant. ICPH 3762 and ICPH 4502, with high per se performance and high standard heterosis for grain yield per plant and for majority of yield attributes, were identified as promising hybrids.
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