Efficiency of four methods of selection in brinjal improvement in relation to resistance to bacterial wilt

Abstract

Bacterial wilt caused by pseudomonas solanacearun is one of the serious problems that limits its cultivation in kerala. With the identification of SM- 6, a brinjal line from Kerala Agricultural University showing considerable degree of resistance to wilt, the prospects of brinjal cultivation has become brighter under the acidic soil conditions of kerala. Studies at the department of Olericulture, Kerala Agriculture University, indicated the presence of transgressive seggregant(s) within SM-6 which were grouped into eleven distinct types. Hence a study was undertaken at the College of Horticulture, Vellanikara to improve upon the existing eleven types for earliness and yield keeping resistance to wilt intact. Each of the eleven genetics groups were improved through four methods of selection mass, single plant, pure line and single seed descent. The selections were conducted in two consecutive cycles. The criteria for selecting elite plant types were fruits/plant and total yield/plant. Observations were recorded on earliness, Vegitative characters, Productive characters and their components. The relative efficiency of the four methods of selection to improve economic characters was critically examined. Being a cross pollinated crop mass selection and single plant selection were found superior to pure line selection and single seed descent to improve economic characters. Genetic information line genotypic co-efficient of variation, phenotypic co-efficient of variation, heritability in the broad sense, genetic advance and genetic advance as percentage of mean was estimated for the progenies developed through four method of selection. The relative efficiency of the four methods of selection was also examined in terms of improving genetic parameters of progenies. Genetic advance as percentage of mean was highest for progenies developed through single plant selection. Realised genetic gain for economic characters as compaired to the overall mean was positive for progenies developed through maas and single plant selections. The eleven genetic groups were also evaluated under each selection method for the characters under study. The genetic groups SH-6-2, SH-5-1 and SH-6-4 were promising for fruits/plant and yield/plant. The level of resistance of sm-6 to bacterial wilt was assessed under four methods of selection. Single seed descent was found effective to improve to improve the level of resistance of sm-6 to bacterial wilt. When screened under field conditions, the genetic groups sm-6-1, sm-6-4,and sm-6-9 exhibited complete plant immunity under all the four methods of selection. In both the cycles. Multi locational trials and artificial inoculation studies further confirmed the resistance of the basic population of sm-6 to bacterial wilt.