Introgression of Tomato Leaf Curl Virus Tolcv Resistant Gene Into Tomato Solanum lycopersicum L Cultivars Through Marker Assisted Backcross Breeding

Abstract

An investigation was carried to validate three markers (TG0302, P1-16 and TES0344) newlinelinked to Ty-2 conferring resistance to ToLCV disease using two F2 populations of the crosses newlineGPBT-08 × CLN2768A and DMT-2 × CLN2777H. All the three molecular markers newlinesegregated in the ratio 1:2:1 (genotypic) and 3:1 (phenotypic) in both the populations. newlineSignificant association of Ty-2 with leaf curl resistance through SMA explained phenotypic newlinevariance of 11.67% and 9.09% of the crosses GPBT-08 × CLN2768A and DMT-2 × newlineCLN2777H respectively. newlineTwo validated markers (P1-16 and TG0302) used to introgress Ty-2 into cultivated newlinevarieties by MABB. Backcross populations which developed by crossing GPBT-08 and newlineDMT-2 as recurrent parents with CLN2768A and CLN2777H as donor parents carry Ty-2 newlineconferring resistance to ToLCV respectively. Carrying Ty-2 conferring resistance to ToLCV. newlineIn BC2F4, GA-27-1, GA-37-9 and GA-40-1 lines of the cross GPBT-08 × CLN2768A and newlineDH-4-8, DH-12-8 and DH-14-5 lines of the cross DMT-2 × CLN2777H recovered highest newlineRPG, exhibited superior performance for yield traits with moderate resistant reaction. In newlineBC3F3 GA-8-5 and GA-12-3 lines of the cross GPBT-08 × CLN2768A and DH-5-6, DH-12-3 newlineand DH-13-3 lines of the cross DMT-2 × CLN2777H recovered highest RPG with superior newlineyield performance and with moderate resistant reaction. These lines appear promising for newlineenhancing tomato production in leaf curl-affected areas or season of southern India. newlineIn another experiment 15 lines were crossed with 3 testers by line × tester method to newlinedevelop 45 hybrids. These hybrids were evaluated for combining ability, heterosis and newlinenaturally screened for the resistance to ToLCV disease. The analysis of variance revealed newlinesignificant differences among the hybrids for all the traits. newlineThe combining ability analysis revealed presence of higher magnitude of SCA newlinevariance than GCA variance for most of the traits under study indicating predominance of newlinenon-additive gene action except for days to 50% flowering. Crosses L2 × T1, L10 × T3 and newlineL1 × T3 exhibi