STUDIES ON DIVERSITY, HETEROSIS AND COMBINING ABILITY IN OKRA [Abelmoschus esculentus (L.) Moench]
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Date
2018-12-12
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K.R.C. COLLEGE OF HORTICULTURE, ARABHAVI (UNIVERSITY OF HORTICULTURAL SCIENCES, BAGALKOT)
Abstract
The investigation on ‘studies on diversity, heterosis and combining ability in okra (Ablemoschus esculentus (L.) Moench.)’ was undertaken at Department of Vegetable Science, Kittur Rani Channamma College of Horticulture, Arabhavi, Belagavi (Karnataka). Genetic variability, correlation, path analysis and diversity were assessed by evaluating 65 genotypes. Among 22 characters studied for genotypic and phenotypic coefficient of variation were highest for fruit yield per plot, fruit yield per hectare and vitamin C. High heritability (h2 bs) coupled with high genetic advance over mean were observed for plant height at 90 days after sowing, internodal length, fruit yield per plot, fruit yield per hectare and vitamin C. Fruit yield per plant had significant and positive association with plant height at 45, 60 and 90 DAS and number of fruits per plant both genotypically and phenotypically. Path analysis studies revealed high direct effect of number of fruits per plant on fruit yield per plant at phenotypic level. Vitamin C contributed maximum to the total genetic diversity among genotypes. Using estimated D2 values 65 genotypes were grouped into 3 clusters. Intra cluster distance was highest in cluster II followed by cluster I. The highest inter cluster distance was noticed between cluster I and III followed by Cluster II and III.
Heterosis and combining ability were determined using 18 lines and 3 testers and subjected to line × tester analysis. Among 54 hybrids, the hybrid which exhibited maximum positive and significant heterosis for fruit yield per hectare over commercial check was noticed in the hybrids L43 × T44 followed by L22 × T36, L22 × T44, L53 × T36 and L31 × T23 and also exhibited significant sca effects for fruit yield per hectare. Among the lines L6, L14, L16, L22, L31, L43 and L53 were identified as good combiners for over all characters based on comprehensive study considering gca effects of 22 characters. Out of 54 crosses, 11 were moderately resistant, 25 were moderately susceptible and 18 were susceptible to fruit borer. Three were resistant, seven were moderately resistant and 44 were moderately susceptible to yellow vein mosaic virus disease. L43 × T44, L22 × T36 and L22 × T44 which are the best hybrids selected for yield per hectare and resistant to YVMV. The fourth best hybrid L53 × T36 and L31 × T23 was found to be moderately resistant to YVMV. Non- additive gene action was more predominant for majority of the yield contributing characters indicating its amenability for recurrent selection apart from heterosis breeding for further development.
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