Molecular Genetics of Salt Tolerance in Tomato F2 Segregating Population with the Aid of RAPD Markers

Abstract

Salt tolerance of segregating progenies of a cross between a domesticated salt sensitive tomato cultivar (CA4) and a natural salt-tolerant wild-type tomato species (LA1606) was characterized. The F1 plants from this cross were selfed and 120 F 2 segregating progenies from the resulting population along with parental CA4 and LA1606 plants were evaluated for salt tolerance. These plants were irrigated everyday with 185 mM NaCl for 82 days and quantitative traits were quantified including number of flowers, fruit number, fruit weight, fruit length, fruit width, fruit set percentage, and total yield. The two parental lines were evaluated for the presence of 27 seven independent RAPD markers and 7 markers were found to be polymorphic for the two genotypes. Bulk Segregant (BSA) analyses consisting of pooling 10 “most tolerant” and 10 “most sensitive” F2 segregating plants showed association of two RAPD polymorphic markers with higher salt tolerance. Two DNA markers that exhibit co-segregation with salt tolerance were identified and characterized. RAPD marker OPX-17 and MRTOMR-022 exhibited 2 positive molecule markers (polymorphism) which were found only in the resistant parent (LA1606) and resistant F2 bulk