GENETIC STUDIES FOR EARLY MATURITY, YIELD AND YIELD ATTRIBUTES IN GROUNDNUT (Arachis hypogaea L.)
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Date
2024-04-26
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Acharya N G Ranga Agricultural University
Abstract
Breeding for earliness in groundnut is always a significant part of the
objectives in many crop improvement programs across the globe. However, limited
studies were available on sources of earliness and its contributing traits coupled with yield
and yield components. No coherent character association studies were available for early
maturity and its contributing traits. Therefore, the present study was conducted to estimate
the extent of genetic variability, genetic divergence and trait associations for high yield,
earliness and their contributing traits in groundnut where thirty six groundnut genotypes
were evaluated in alpha lattice design with two replications at Regional Agricultural
Research Station, Tirupati, during Rabi, 2021-22. Variability among all the 36 genotypes
is highly significant for all the traits studied. Of all the thirty six entries tested, TAG 24,
TCGS 2339, TCGS 2326, UBEK 21-40, UBEK 21-43 and UBEK 21-74 were noteworthy
early maturing entries (90 days) with superior agronomic characters. All these genotypes
were visualized with 100 pod weight below 90g, 100 kernel weight below 40g and harvest
index below 50%. These characters are to be confirmed in future studies and in designing
ideal plant type for early maturity. Study of genetic variability revealed high PCV and
GCV for characters viz., days from opening of 1st flower to opening of 25 number of
flowers and number of primary and secondary branches per plant. High heritability
coupled with high genetic advance as per cent of mean were recorded for days from
opening of 1st flower to opening of 25, 40, 50 number of flowers, plant height, number of
primary and secondary branches per plant, number of mature pods per plant, harvest
index, 100 pod weight and 100 kernel weight. Genetic divergence studies revealed the
diversity among 36 genotypes by grouping them into 6 clusters. Maximum inter cluster
distance was observed between cluster VI and III followed by cluster V and III, cluster II
and III, cluster IV and VI and cluster I and VI. Genotypes from cluster III and genotype
(UBEK 21-67) from cluster IV can be selected for developing early maturing genotypes.
To develop genotypes with higher pod yields, genotypes from cluster II and V are to be
utilized in hybridization programs. Character association studies revealed two
phenological traits viz., days to accumulation of 25 and 40 flowers from emergence
contributed significantly to days to maturity. Even though other traits exhibited
significant inter-se correlations among them, their association with days to maturity was
negligible. Therefore, for developing early maturing genotypes, selection for early
accumulation of 25 and 40 flowers from emergence would be advantageous. For pod
yield plant-1, significant positive correlations were observed with days to maturity, seed
yield plant-1, number of mature pods plant-1, 100 pod weight, 100 kernel weight and
harvest index but number of immature pods plant-1 was observed to be negatively
correlated. Thus, for developing high yielders, selection should be focused on number of
mature pods plant-1, days to maturity, harvest index, 100 pod weight, 100 kernel weight
and seed yield plant-1. For developing early maturing genotypes with optimum yield
levels, selection criteria could be days to accumulation of 25 flowers and 40 flowers from
emergence with optimal number of ripened pods at 90 days duration with a harvest index
(<50%), 100 pod weight (90g) and 100 kernel weight (<40g).