Determining heterotic response, combining ability and gene action for yield and yield contributing TRAITS IN COWPEA (Vigna unguiculata (L.) Walp.)
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Date
2014-08
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G.B. Pant University of Agriculture & Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation was carried out during 2012-2013 at G.B. Pant University of
agriculture and Technology, Pantnagar. First experiment was undertaken to estimate the relative importance of combining ability and heterosis for 11 quantitative characters including seed yield in cowpea (Vigina unguculata (L). Walp). Second experiment was conducted to understand the nature of gene effects involved in the inheritance of various quantitative characters. Pant Lobia-1, Pant Lobia-2, Pant Lobia-3, PGCP-12, PGCP-14, Bucksora Local and Pant Vegetable-3 along with their 21 F1’s were evaluated for genetic analysis using Griffing’s numerical approach (1956). Six generations viz;- P1, P2, F1, F2, BC1 and BC2 of each three families, PGCP-12 x PGCP-14 (Family 1), Pant Lobia-1x PGCP-
14 (Family 2), Pant Lobia-1x Pant Lobia-3 (Family 3), were evaluated in Compact Family Block Design with three replications and data were subjected to generation mean analysis following scaling test (Mather 1949).
Analysis of variance revealed significant mean squares of general and specific combining
abilities (GCA and SCA) for all the traits studied. Pant lobia-2 and Pant Lobia-3 had good GCA for seed yield per hectare. Pant Lobia-1 was best general combiner for 100-seed weight and number of pods per plant whereas, Pant Lobia-2 was found to be good general combining ability for number of pods per plant, seed yield per hectare and seed weight per plant. The parent Pant Lobia-3 had good general combiner for seed yield per hectare, seed weight per plant and days to pod maturity whereas, PGCP-12 was good general combiner for plant height, seed yield per hectare, 100-seed weight and seed weight per plant. Buksoura Local and PVCP-3 were good general combiners for green pod weight per plant and pod length.
The hybrids PGCP-12 x PGCP-14 and PGCP-14 x PVCP-3 revealed highest SCA effects for
seed yield per hectare. The magnitude of relative heterosis, heterobelteosis and economic heterosis for seed yield per hectare ranged from -18.24 to 63.34%, -18 .40 to 47.69% and -4.66 to 93.40% respectively. Pant Lobia-2 x Pant Lobia-3 was best cross combination for days to 1st flowering, Pant Lobia-2 x PVCP-3 for days to pod maturity, Pant Lobia-1x Pant Lobia-2 for number of pods per plant. Cross PGCP-14 x PVCP-3 showed highest value for pod length, Pant Lobia-3 x PGCP-12 was the best cross combination for plant height. Cross PGCP-12 x PGCP-14 gave highest positive SCA effect for green pod weight per plant. For number of seeds per pod Pant Lobia-3 x PGCP-12 was the best cross combination, Cross PGCP-14 x PVCP-3 for seed weight per plant and the Cross Pant Lobia-1 x Pant Lobia-3 for 100-seed weight. Significant estimates of additive [d] and dominance [h] effects as well as
all three epistasis were observed for most of the quantitative characters in all the three families. The opposite signs of [h] and [l] indicated that duplicate epistasis was important in inheritance for some of the traits in all the three families. In the present investigation both additive and non-additive gene actions were involved in controlling seed yield and related traits. The presence of additive gene action suggested that a part of the heterosis can be fixed in subsequent generations to take advantage in further selection. The preponderance of non-additive gene action, however brought out that heterosis component could be explained in hybrid development in cowpea.
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Thesis-PhD
Keywords
heterosis, combining ability, gene action, yield components, cowpeas, vigna unguiculata, hybridization