ASSESSMENT OF GENETIC AND MOLECULAR VARIABILITY IN WATER SPINACH (Ipomoea aquatica Forsk.) GENOTYPES AND THEIR SUITABILITY FOR CULTIVATION UNDER CONTAINER GARDENING
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Date
2019
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
The present investigation entitled “Assessment of genetic and molecular variability in water spinach (Ipomoea aquatica Forsk.) genotypes and their suitability for cultivation under container gardening” was conducted at “Research and Instructional Farm Horticulture, Department of Vegetable Science, Indira Gandhi Krishi Vishwavidyalaya”, Raipur (C.G.) during the years 2017-18 and 2018-19.
The experiment was laid out in completely randomized design in three replications with 24 genotypes (treatments) to estimate the genetic and molecular variability, character association, path analysis, heritability, genetic advance and cluster analysis. Observations were recorded on five competitive random plants from each replication.
Analysis of variance revealed significant differences for all characters. As per the mean performance of water spinach genotypes in respect to green foliage yield (kg/container), IGWS-2 (14.60 kg) was found superior than the other genotypes evaluated.
All the genotypes showed a wide range of variation. PCV (Phenotypic coefficient of variance) was higher than the GCV (Genotypic coefficient of variance) for all the characters. Genotypic as well as phenotypic coefficient of variance were recorded in high magnitude for traits viz., vine length (cm), number of vines per plant, number of leaves per plant, inter node length (cm), number of nodes per vine, leaf width (cm), leaf length (cm), petiole length (cm), leaf : vine ratio, fresh weight of leaves (g), green foliage yield per plant (g) and green foliage yield (kg/container). High heritability coupled with high genetic advance was observed for vine length, number of vines per plant, leaf width, number of leaves per plant, internode length, number of nodes per vine, leaf length, petiole length, leaf:vine ratio, fresh weight of leaves, dry weight of leaves, green foliage yield per plant and green foliage yield (kg/container).
Correlation coefficient analysis of green foliage yield (kg/container) showed highly significant positive correlation with green foliage yield per plant at both phenotypic and genotypic level respectively. Highly significant positive correlation between green foliage yield (kg/container) and moisture per cent of foliage was found at genotypic level.
Analysis of path coefficient revealed that number of nodes per vine had maximum positive direct effect on foliage yield kg/container followed by dry weight of leaves, green foliage yield per plant, internode length, leaf width and number of vines per plant. The findings also indicates that these characters are the main contributors to the green foliage yield (kg/container). Number of nodes per vine had maximum positive indirect effect on foliage yield via vine length followed by via number of leaves per vine and via inter node length and this will lead to development of high yielding varieties ultimately.
Three clusters were formed when divergence analysis of the genotypes was done on the basis of genotypic data. Maximum genotypes appeared in cluster I which possessed 16 genotypes, followed by cluster III with 6 genotypes while cluster II had minimum number of genotypes (2), leads to the conclusion that all the genotypes are rich in diversity which are selected for evaluation in this experimental trial. On the basis of experimental findings it is also suggested that, there is no relationship between genetic diversity and geographical area as genotype chosen from different eco-geographical regions are grouped in different clusters.
28%-93% similarity was observed for water spinach genotypes when their molecular analysis using SSR markers was done. The dendrogram constructed using the molecular data helped to classify the genotypes into three large clusters. Cluster I contained genotypes IGWS-16 and IGWS-26. Least similarity index was shown by “Cluster 1”. This means the genotypes present in this cluster showed the maximum diversity from others.
Water spinach genotypes IGWS-2, IGWS-1, IGWS-26, IGWS-9, and IGWS-4 were found better for container gardening in terms of green foliage yield (kg/container) and can be considered for further varietal improvement programme.
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