“GENETIC VARIATION, SELECTION INDICES AND DIVERSITY ANALYSIS FOR POD YIELD AND ITS COMPONENTS IN RILs OF GROUNDNUT (Arachis hypogaea L.)” 2912
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Date
2019-08
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JAU, JUNAGADH
Abstract
An investigation was carried-out on genetic variability, correlation, path
analysis, selection indices and genetic divergence in groundnut using 68 genotypes
comprising 64 Recombinant Inbred Lines, two parents and two checks. The genotypes
were evaluated in a Randomized Block Design with three replications at the Main
Oilseeds Research Station, J.A.U., Junagadh during kharif 2018.
The observations were recorded on five randomly selected plants from each
replication and their mean values were used for statistical analysis. The characters
studied were days to 50% flowering, days to maturity, plant height (cm), SCMR,
number of mature pods per plant, number of immature pods per plant, shelling
percentage (%), 100-kernel weight (g), sound mature kernels (%), kernel yield per
plant, biological yield per plant (g), pod yield per plant (g), harvest index (%) and oil
content (%).
Analysis of variance revealed significant differences among the genotypes for
all the 14 characters studied. Wide to moderate range of variation was observed for
majority of the characters. Wide range of variation was observed for biological yield
per plant, number of mature pods per plant, SCMR, plant height, 100-kernel weight and
harvest index.
The values of PCV were slightly higher than that of GCV for all the traits. The
highest GCV and PCV were observed for number of immature pods per plant. The
values were observed to be moderate for biological yield per plant, number of mature
pods per plant, 100-kernel weight, kernel yield per plant and pod yield per plant.High estimates of heritability were observed for all the 14 characters, while high
heritability along with high genetic advance was observed for number of immature pods
per plant, biological yield per plant, number of mature pods per plant, 100-kernel
weight and kernel yield per plant.
The values of genotypic correlations were higher than their corresponding
phenotypic correlations. The pod yield per plant exhibited significant and positive
correlation with days to 50% flowering, days to maturity, number of mature pods per
plant, kernel yield per plant and biological yield per plant at both genotypic and
phenotypic levels. The path coefficient analysis showed the highest positive direct as
well as appreciable indirect influences on pod yield per plant through kernel yield per
plant and biological yield per plant.
A total of 63 selection indices were constructed involving pod yield per plant
and five yield components using the discriminant function technique. The discriminant
function selection had higher genetic gain and selection efficiency over straight
selection for pod yield alone. The efficiency of selection increased with the inclusion
of more number of characters in the index. A selection index consisting of pod yield
per plant, days to 50% flowering, days to maturity, number of mature pods per plant
and biological yield per plant and an index involving pod yield per plant, days to 50%
flowering, days to maturity, kernel yield per plant and biological yield per plant could
be advantageously exploited in groundnut breeding.
Sixty eight genotypes were grouped into 5 clusters by Mahalanobis’s D2
statistic. The maximum inter-cluster distance was found between clusters IV and V
followed by that between clusters III and V, I and V, II and V and II and IV. The cluster
V was superior for pod yield per plant, kernel yield per plant, number of mature pods
per plant, number of immature pods per plant, plant height, SCMR, 100-kernel weight,
shelling out-turn, biological yield per plant and oil content, while cluster III was the
best for harvest index, sound mature kernels and days to 50% flowering. Cluster IV was
good for days to maturity. The number of immature pods per plant, days to maturity
and biological yield per plant contributed maximum towards the total divergence.
Based on high yielding genotypes and large inter-cluster distances, it would be
advantageous to attempt crossing of the genotypes from cluster V with the genotypes
of clusters IV, III, II and I which may lead to the generation of broad spectrum of
favourable genetic variability for yield improvement in groundnut.