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GENETIC DIVERGENCE STUDIES IN CASSAVA [Manihot esculenta Crantz]

KrishiKosh

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Title GENETIC DIVERGENCE STUDIES IN CASSAVA [Manihot esculenta Crantz]
 
Creator BANAVATHU BABU RAO
 
Contributor Dr. P. ASHOK
 
Subject magnitude,quantitative characters,RBD,genotype PDP
 
Description The experiment was taken up to elicit the information on magnitude of genetic variability, heritability and to predict the gains realized through selection, character association, cause and effect relationship and divergence for the quantitative characters in cassava (Manihot esculenta Crantz) genotypes. Eighteen genotypes of cassava were evaluated in RBD with three replications during kharif season of 2012 at Horticultural College and Research Institute, Dr. Y. S. R. Horticultural University, Venkataramannagudem, West Godavari district, Andhra Pradesh.

The study revealed significant differences among genotypes for different characters studied. Among all the genotypes studied, genotype PDP accession-10 recorded the highest tuber yield per hectare and found suitable to the local agro-climatic conditions. The genotypes H-165 and Sree Padmanabha (MNga-1) were also found to be elite for different characters.

Among the characters studied, high PCV and GCV were observed for characters like number of leaves per plant, total leaf area, height of first branching and HCN content indicating high variability available in the germplasm for these characters for further improvement.

High heritability coupled with high genetic advance as per cent of mean was observed for characters number of leaves per plant, total leaf area, height of first branching, stem diameter, tuber dry matter content, starch content, HCN content and tuber yield per hectare, which indicated that these characters were least influenced by the environmental effects, and these characters were governed by additive genes and selection will be rewarding for improvement of such traits.

The tuber yield per hectare (t/ha) had significant positive correlation with traits like petiole length, number of leaves per plant, total leaf area, stem diameter, tuber diameter, plant dry matter content, starch content and HCN content suggesting the importance of these traits in selection for yield and can be identified as yield attributing characters for the genetic improvement of yield in cassava.

The tuber yield per hectare (t/ha) was result of direct effect of number of leaves per plant, stem diameter, number of tubers per plant, tuber diameter and plant dry matter content. The high direct effect of these traits appeared to be the main factor for their strong association with tuber yield per hectare.

Analysis for divergence using D2 statistic revealed highly significant differences for different traits, grouping the 18 genotypes into 5 clusters. Cluster IV had the maximum number of genotypes (7) followed by cluster I (5). Maximum inter cluster distance was observed between clusters IV and V while the intra cluster distance was maximum in cluster IV. The highest per cent contribution to divergence came from tuber dry matter content, plant dry matter content, height of first branching, starch content, number of leaves per plant and stem diameter, which suggested that selection of one or two elite genotypes from divergent (IV & V) and (II & V) clusters based on the above characters and crossing would result in more heterosis and novel hybrids.
 
Date 2016-07-25T10:46:58Z
2016-07-25T10:46:58Z
2013-08
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/69678
 
Language en
 
Format application/pdf
 
Publisher Dr. Y. S. R. HORTICULTURAL UNIVERSITY