Genetic Variability and Correlation for Traits Related to Drought Tolerance in Groundnut (Arachis hypogaea L.) under Different Water Regimes

Abstract

The understanding of the variability existing in a population base of crop is pivotal to crop improvement. This study examined the variance components, heritability estimates and correlations between some morphological and physiological traits related to drought tolerance in groundnuts under two water regimes, to speed up the selection and breeding of groundnut genotypes tolerant to drought. The experiment was carried at the Research Farm of the Institute for Agricultural Research, Ahmadu Bello University. Data collected for performance evaluation were number of days to 50% flowering, plant height, number of pods/plant, seed weight/plant and pod yield/plant. Physiological traits related to drought tolerance measured included, Harvest Index (HI), SPAD Chlorophyll meter reading (SCMR) at 40, 60 and 80 Days after showing (DAS). Variance components, Genetic Coefficient of Variation (GCV), Phenotypic Coefficient of Variation (PCV) and broad-sense heritability were calculated for all the traits recorded. Results showed that number of pods/plant, seed weight/plant, SCMR at 60 DAS and HI showed a strong positive and highly significant (P<0.01) with pod yield/plant in all watering conditions. Heritability of the traits ranged from 8.16%- 60.00% with pod yield/plant having the highest value and days to 50% flowering having the lowest values in non-stress (NS), while under water stress condition, heritability was low to moderate from 0.53-53.33%. The SCMR at 60 DAS, number of pods/plant and HI had moderate heritability and significant correlation with pod yield/plant under water stress condition, these traits could be useful criteria in drought tolerance selection.