Inheritance and Identification of Molecular Markers Linked to Tomato Leaf Curl Virus Resistance in Tomato (Solanum lycopersicum Mill.)
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Date
2015-07
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University of Agricultural Science, Dharwad
Abstract
Tomato is an important vegetable crop grown in tropical and subtropical regions of the world. Among all diseases, Tomato Leaf Curl Virus (ToLCV) is of major concern. The present investigation was carried to understand the genetics of ToLCV resistance using segregating populations of Pusa Ruby × CLN2768A and Pusa Ruby × CLN2777H and to identify molecular markers linked to ToLCV disease resistance. The study revealed that the resistance was governed by two dominant genes with 9 : 7 ratio in both the crosses.
To tag the marker linked to ToLCV resistance, a total of 66 SSR markers were employed. Among the 4 polymorphic markers obtained upon parental polymorphism screening, one marker TG0302 was found putatively linked to ToLCV resistance through bulk segregant analysis. Further single marker analysis revealed the phenotypic variance of the marker to the extent 28.1 and 26.71 per cent in the crosses Pusa Ruby × CLN2768A and Pusa Ruby × CLN2777H respectively.
The generation mean analysis indicated duplicate gene action for plant height, number of primary branches, number of fruits per plant and fruit shape index in both the crosses. The presence of significant dominance x dominance type gene action for most of the traits studied, indicate the scope for hybridization to exploit heterosis. Ten superior lines were identified from both the crosses for yield and contributing traits. Less number of whiteflies settled on CLN2768A and CLN2777H and resistant genotypes of F2, B1 and B2 of both the crosses. Higher glandular trichome density on leaf lamina and midvein was recorded in resistant cultivars than that of susceptible ones. Anatomical characters of leaf indicated that resistant genotypes had higher palisade length, palisade number; cortex cell density and sucking distance than susceptible cultivars.
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