STUDIES ON GENETIC VARIABILITY AND CAUSE-EFFECT RELATIONSHIP IN OKRA [Abelmoschus esculentus (L.) MOENCH] GENOTYPES FOR SUMMER SEASON
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Date
2021
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DRPCAU, PUSA
Abstract
The present research programme entitled “Studies on genetic variability and cause-effect relationship in okra [Abelmoschus esculentus (L.) Moench] genotypes for summer season” was conducted with thirty okra genotypes collected from various places across the country at the Hi-Tech Horticulture Farm of the Department of Horticulture of Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar, during the summer season of 2020. The material was assessed using RBD (Randomized Block Design) with three replications. Fifteen traits were selected for the study viz., “plant height (cm), number of primary branches per plant, days to first flowering, days to fruit set, days to first harvesting, number of fruits per plant, number of seeds per fruit, average fruit weight (g), internodal length (cm), number of nodes per plant, number of first flowering nodes, fruit length (cm), fruit diameter (cm), number of ridges per fruit, fruit yield per plant (kg)”
ANOVA exhibited significant mean sum of square (MSS) values due to genotype for all variables under study, which signify the presence of substantial amount of variability in the okra genotypes used for the study. The phenotypic coefficient of variation (PCV) values was slightly greater than the genotypic coefficient of variation
(GCV) values for most of the traits, which was attributed for the minor impact of environment on the morphology of the traits. In the study, high level of heritability associated with high level of genetic advance was observed for “number of primary branches per plant, number of first flowering nodes, number of seeds per fruit, number of fruits per plant, fruit length, fruit yield per plant”, which revealed the preponderance of additive gene action. Therefore, response to early selection may be effective in improving these traits.
Based on correlation and path analysis, “number of fruits per plant, average fruit weight, fruit length” expressed positive and significant correlation with “fruit yield per plant” having their positive direct effect suggesting that during selection these traits may be considered as prime trait to improve yield of okra.
Based on diversity using Tocher's method, the thirty genotypes were grouped into eight different clusters. The inter cluster distances were recorded higher than the intra cluster distances further indicating a considerable amount of diversity in the genotypes involved. Highest inter-cluster distance was found between cluster III and VII followed by cluster V and VII. Among all the characters studied, “fruit length” contributed maximum to the diversity followed by “number of first flowering nodes, number of primary branches per plant”. Further, genotypes VRO-65 (cluster III) and SKY/DR/RS-13 (cluster VI) were selected as superior lines based on high inter cluster distance alongside mean performance for most of yield attributing traits suggesting that these genotypes may be used in crossing programme to obtain heterotic recombinants as well as transgressive segregants.