GENETIC ARCHITECTURE OF SPANISH BUNCH GROUNDNUT (Arachis hypogaea L.)
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Date
2019-07
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jau.junagadh
Abstract
An investigation was carried out using 100 genotypes of groundnut to find out the genetic variability, correlation coefficients, path coefficients and genetic divergence. The material was evaluated in a randomized block design with three replications at the Main Oilseeds Research Station, J. A. U., Junagadh during kharif 2018-19. The observations were recorded on 12 characters viz., days to 50% flowering, days to maturity, plant height (cm), number of primary branches per plant, number of mature pods per plant, number of immature pods per plant, kernel yield per plant (g), pod yield per plant (g), biological yield per plant (g), oil content (%), harvest index (%) and shelling out-turn (%).
Analysis of variance revealed significant differences among the genotypes for all the 11 characters except shelling out-turn was non-significant. The highest range of variation was observed for number of immature pods per plant followed by number of mature pods per plant, kernel yield per plant and pod yield per plant. The high to moderate genotypic coefficient of variation and phenotypic coefficient of variation was observed for number of mature pods per plant followed by number of immature pods per plant, kernel yield per plant, pod yield per plant, biological yield per plant and harvest index. high estimates of heritability coupled with high genetic advance expressed as percentage of mean were observed for number of mature pods per plant, number of immature pods per plant, kernel yield per plant, pod yield per plant, biological yield per plant and harvest index which may be attributed to the preponderance of additive gene action and possess high selective value and thus,
selection pressure could profitably be applied on these characters for their rationale improvement.
The values of genotypic correlation were higher than their corresponding phenotypic correlations. The pod yield per plant exhibited significant and positive correlation with number of mature pods per plant, kernel yield per plant, oil content and harvest index at both genotypic and phenotypic levels. The path coefficient analysis revealed high and positive direct effects of kernel yield per plant, biological yield per plant and harvest index on pod yield per plant. Days to maturity, plant height and number of primary branches per plant had low and positive direct effect. Thus, these characters turned-out to be the major components of pod yield.
The 100 genotypes were grouped into 9 clusters by Mahalanobis’s D2-statistic. The clustering pattern of the genotypes did not show any relationship between geographical distribution and genetic divergence. The maximum inter-cluster distance was found between clusters VI and VIII followed by that between clusters I and VI, V and VI, IV and VI, III and VI, I and IX. The cluster VI was best for kernel yield per plant, pod yield per plant, biological yield per plant and number of immatured pods per plant. The cluster VIII was best for plant height and oil content. The clusters III had desirable value for plant height. Because it shows the longer plant height. The cluster IX was best for number of branches per plant and harvest index. The cluster IV was best for number of matured pods per plant. The cluster I was the best for days to 50% flowering and days to maturity. Because it shows the early flowering with early maturity. The number of matured pod per plant followed by kernel yield per plant, days to 50% flowering, plant height, oil content, number of matured pod per plant and biological yield per plant contributed maximum towards divergence, it is advisable to attempt crossing of the genotypes from cluster VI with the genotypes of cluster VIII as well as I and V and IV, which may lead to broad spectrum of favourable genetic variability for yield improvement in groundnut.