Analysis of variability in morphological and molecular characteristics of Melia dubia Cav.Syn. Melia composita Willd.”
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Date
2021-03-04
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College of Horticulture and Forestry, Central Agricultural University, Pasighat
Abstract
In the present study, ANOVA using CRD was conducted which revealed significant differences among the selected plus trees for all characters studied. The highest GCV and PCV was observed as 29.19 and 31.31 respectively. The GCV is found to have lower magnitude than the PCV for all the traits. This implies that these traits are influenced by the local environmental factors. Heritability varied from 87% to 98%, the first 4 traits have high heritability values accompanied with high genetic advance which indicates strong additive gene action. High heritability but low genetic advance was observed in pulp thickness which indicate presence of non-additive gene effects and high environmental interaction.
Themaximum inter-distance(4943.48) was found between cluster-3 and cluster-4. The minimum inter-cluster distance(501.93) was recorded between cluster-2 and cluster-4 indicating genetic closenesss. The maximum intra-cluster distance(164.21) was found in cluster-1 and the minimum was found in cluster-5 with an intra-cluster distance zero. The maximum intra-cluster distance shown by cluster 1 implies greater genetic diversity than other clusters.
The 34 plus trees were grouped into five clusters through cluster analysis. Cluster 1 had a maximum number of CPTs with 26 genotyps, whereas the least number observed for cluster 5 with just 1 genotype. Clusters with only one plus tree can either possess superior or inferior quality among the plus trees. The clustering pattern indicates that plus trees from the same geographic sources were grouped into different clusters and vice-versa.
PCA of the morphological characters revealed the first three components have the eigenvalues greater than one and cumulatively accounted for 94.8% of the total variation.
The protocol of genomic DNA extraction by Swati et al. (2016) as described by Doyle and Doyle, (1987) was used in the present study.The concentration of genomic DNA from juvenile leaves of Melia dubia with absorbance ratio (A260/A280) ranged from 1.71 to 2.30. The highest average expected genetic diversity (h) (0.47) was obtained with primer C31 and lowest (0.35) with primer MAC69.The highest polymorphism (PIC) was reported with primer C31 (0.48) and lowest (0.35) with primer MAC69. The selected plus trees were amplifiedusing 15 SSR markers, of which 5 primers were found to be polymorphic. The UPGMA dendrogram was generated, which resulted in the formation of 8 clusters, where the biggest cluster was found in cluster 1 with 15 different genotypes. The genetic dissimilarity between pair-wise comparisons of the genotypes using NTSYS. The overall dissimilarity values among the selected plus trees ranged from 0.00 to 0.85. Though overall correlation between matrices was low (r=-0.04426, p=0.2212), both morphological and molecular dendogram clustered various progenies on least similar patterns.
Description
The present study was undertakenduring 2018-20to analyse the morphological and molecular variability in characteristics of Melia dubia selectedfrom different villages of East Siang District, Arunachal Pradesh.Based on selection index method,34 phenotypically superior trees were identified from 11 villagesof East Siang District. The following parameters were recorded: tree height (cm), clear bole height (cm), girth at breast height (cm), collar girth (cm), straightness, branching behavior and GPS coordinates. The fruit and seed morphology for the 34 plus trees were characterized and molecular variation was studied using 15 SSR markers.
Among the selected plus trees,tree height, CBH, GBH, CG, straightness and branching behaviour varied from830 cm to 1500 cm, 230 cm to 600 cm, 52.6 cm to 162 cm, 55.2 cm to 170 cm, 3 to 4 and 2 to 4 respectively