Classification of different varieties and new accessions of mango (Mangifera indica L.) based on qualitative traits and assessment of genetic diversity
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Date
2016-10
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G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand)
Abstract
The present investigation was carried out in different varieties of mango during the years 2014 and 2016 at GBPUA&T, Pantnagar with objectives of characterization and grouping of genotypes based on qualitative traits and to assess the genetic variability and diversity in different varieties using principal component analysis (PCA) and D2 statistics. The experimental materials were evaluated under Randomized Block Design with three replications. The observations were recorded on morphological and physico-chemical characters covering 25 qualitative & 27 quantitative traits and the data were analyzed by appropriate statistical and Biometrical tools.
The morphological qualitative traits showed wide variations among different mango varieties. Analysis of variance showed adequate amount of genetic variability among different varieties for most of the characters. The fruit characters namely fruit weight, length, width, pulp weight and pulp: stone ratio varied from 20.07-420.65 g, 3.48-13.28 cm, 2.81-8.70 cm, 13.15351.64 g and 2.50-10.33, respectively. The TSS, total sugar, non reducing sugar and total carotenoids varied from 12.06-22.320B, 11.36-20.69 %, 8.32-14.62 % and 1.78-9.23 mg/100 g, respectively. The phenotypic and genotypic coefficient of variation were found higher for number of fruits per tree at harvesting, yield per tree, total carotenoid, pulp weight, fruit weight, peel weight, stone weight and pulp: stone ratio, while these were moderate to low for remaining traits. High heritability coupled with moderate to high genetic advance was found for most of the characters, while lower genetic advance recorded for leaf length and leaf width. The genotypic correlation coefficient was higher than phenotypic correlation coefficient for most of the characters and yield per tree showed significant positive correlation with fruit weight, fruit length, fruit width, stone length, stone width, pulp weight, pulp: stone ratio, ascorbic acid, number of fruits per tree and total carotenoids, while negative with acidity. The assessment of genetic divergence revealed sufficient variability among the different varieties of mango. Principal component analysis indicated that first ten components accounted for more than 86.07 % of the total genetic variation. The characters contributing more positively with PC1 and exhibited maximum variability among the varieties for leaf area, leaf length, yield per tree, fruit weight, size, stone weight, stone size, peel weight and total sugar. Cluster analysis using D2 statistics grouped different mango varieties into seven clusters during both the years as well as on the basis of pooled data of two years. Therefore, it would appear logical to affect crosses between varieties belonging to the clusters separated by high estimated statistical distance. In pooled analysis, the inter-cluster average D2 value was found maximum (513.38) between cluster III with eight varieties and VII with a single variety. The promising clusters were identified on the basis of cluster mean value of pooled analysis for desirable traits viz., cluster III for maximum duration of fruit maturity, fruit weight, fruit size, stone weight, stone size, pulp and peel weight; cluster IV for higher yield per tree, length and width of inflorescence and cluster VI for TSS, reducing sugar, non reducing sugar, total sugar and total carotenoids.
Therefore, it may be concluded that morphological qualitative traits can be used for proper characterization, grouping of genotypes and varietal identification. Results of PCA and D2 analysis indicated substantial variation among the varieties and new accessions of mango with respect to different morphological and physico-chemical quantitative traits, which may help the mango breeders for future breeding programme.
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Horticulture