Genetic variability in chilli(Capsicum annuum L.) with emphasis to reaction to leaf curl virus

Abstract

The present investigation entitled "Genetic variability in chilli (Capsicum annuum L.) with emphasis to reaction to leaf curl virus" was conducted at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2000-2001. The data for the investigation were collected from two field experiments, each laid out in Randomised Block Design with three replications. The second experiment was conducted without taking any control measures against leaf curl virus. The 37 genotypes included in the study showed significant difference for all the 15 traits. The maximum values for phenotypic coefficient of variation (pC V) genotypic coefficient of variation (GC V) were recorded for fruit yield per plant and the minimum values for crop duration. PCV and GCV were high for fruit yield per plant, number of fruits per plant, average fruit weight, vulnerability index, fruit girth and number of flowers per plant. These traits also showed high heritability coupled with high genetic advance. Yield per plant was positively correlated with number offruits per plant, average fruit weight, number of secondary branches, number of flowers per plant, fruiting span and crop duration. Path analysis revealed high positive direct effect for average fruit weight, number of fruits per plant and crop duration. Hence selection for these traits can improve yield.

The 37 genotypes were grouped into four clusters based on Mahalanobis D2 statistic. Cluster I was largest with 23 genotypes while cluster IV had only one genotype. Cluster n had eight and cluster III had five cultivars respectively. Cluster IV containing a single variety was superior to the other clusters in respect of desirable characters. Field screening of the 37 cultivars for leaf curl resistance (experiment Il) showed that eight genotypes were tolerant to the disease while 27 were susceptible and two were highly susceptible to the disease. Comparison of yield and vulnerability index in both experiments showed that reduction in yield was less in tolerant varieties than in susceptible ones. The performance of T 26, T 3 and T 13 were comparable under controlled and uncontrolled conditions. The genotype T 13 was identified as a desirable accession as it produced high yields inspite of the disease. Correlation analysis showed negative association of yield with vulnerability index in both experiments indicating that susceptibility to the disease leads to a reduction in yield. The high yielding types and leaf curl tolerant types identified from the study could be used as parents in crop improvement programme to evolve high yielding leaf curl tolerant varieties.