Genetic analysis of segregating generations for yield attributesand resistance to fruit and shoot borer (Earias vittella Fab.) in bhindi (Abelmoschus spp.)

Abstract

The research study entitled “Genetic analysis for yield attributes and resistance to shoot and fruit borer (Earias Vittella Fab.) in Bhindi (Abelmoschus spp.)” was undertaken during the period 2006-2008 at Department of plant Breeding and Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara, Thrissur. The main objectives of this project were to study the nature of gene action governing fruit and shoot borer resistance and yield attributes and to attempt for transfer of shoot and fruit borer resistance to genotypes with desirable yield attributes. Six diverse okra genotypes viz, Arka Anamika, KL9, Salkeerthy, Sel 2, Susthira and AC5 were crossed in a 6 x 6 complete diallel pattern. Thirty crosses were made out of which 24 Fjs were fertile and six interspecific crosses were sterile. Fifteen selected F2S were evaluated for yield attributes and resistance to fruit and shoot borer. High genetic variability, heritability and genetic gain were observed in fruit weight and plant height. Both Fi and F2 of the cross Arka Anamika x Salkeerthy recorded the higher fruit yield than others. Arka Anamika was found to be a good general combiner for fruit number, fruit weight and fruit length. KL9 showed high gca for days to first flowering, intemodal number and fruit weight. Fruit yield was positively associated with number of fruits, number of intemodes, fruit weight and fruit length. Shoot and fruit borer infestation recorded- negative association with plant height, flowering period, fruit number, fruit yield and intemodal length. Overdominance was observed for most of the yield contributing traits. Generation mean analysis for six generations from two crosses viz. Sel 2 x AC 5 and KL 9 x Salkeerthy were carried out and gene action for yield attributes and resistance to fruit and shoot were studied. Duplicate non allelic interactions were observed for most of the traits studied. Complementary epistasis govern the inheritance of fruit borer resistance in the cross Sel 2 x AC 5. Digenic non-allelic interaction model was found inadequate to explain shoot borer infestation. Biochemical analysis indicated the presence of higher levels of phenol and tannin content in fruits and shoots of resistant genotypes. The Fi of the cross Sel 2 x AC 5 was identified as the best hybrid for both marketable fruit yield and resistance to fruit and shoot borer and it also showed field resistance to Yellow Vein Mosaic Virus.