Screening of chilli genotypes for resistance to bacterial wilt and mosaic

Abstract

The investigation on "Screening of chilli (Capsicum annuum L.) genotypes for

resistance to bacterial wilt and mosaic" was conducted at the vegetable research farm of Department ofOlericulture, College of Horticulture, Vellanikkara during 1997-'98.

Fifty three chilli accessions collected from various parts of the country and abroad were evaluated in the wilt sick soil. The level of resistance to bacterial wilt varied with the accessions, Out of the 53 accessions tested, 15 were resistant, 16 were moderately resistant, 13 were moderately susceptible, and the remaining nine were highly susceptible. Among the 15 resistant accessions nine were short fruited, five were long fruited and remaining one was medium long fruited. The chilli lines were catalogued as per the IBPGR descriptor. The extent of genetic variability for 13 characters viz. plant height, plant spread, days to first flower, days to first harvest, fruit length, fruit girth, pedicel length, number of fruits per plant, average fruit weight, fruit yield per plant, driage, number of harvests and total . duration were studied. The genotypic and phenotypic coefficients of variation, heritability, genetic advance and genetic gain were estimated.

Significant differences were observed among the 53 genotypes for almost all the characters studied. Among the 53 genotypes the earliest flowering (59 days) genotype was CA 715 and the highest yielding (352.75 g) genotype was CA 728. CA 731 recorded the maximum number of fruits (108.50) per plant. High heritability coupled with high genetic gain was observed for the characters - fruit length, fruit girth, number of fruits per plant, average fruit weight and fruit yield per plant. The highest positive correlation with yield was expressed by the total duration. Average fruit weight exhibited the highest positive direct effect on yield. Based on the genetic divergence the 53 genotypes were grouped into seven clusters.

Out of 53 accessions evaluated for mosaic resistance, nine were resistant, twelve moderately resistant and the remaining 32 were susceptible. The resistance showed by the nine accessions was confirmed by standard methods. The accessions CA 337, CA 731, CA 738, CA 739 and CA 744 were found to possess the resistance to both bacterial wilt and mosaic and can be recommended for disease prone areas. The F IS developed using the resistant parents were found susceptible to both bacterial wilt and mosaic.