Genetic analysis and identification of molecular marker linked to the gene for fruit skin colour in eggplant (Solanum melongena L.)

Abstract

Eggplant or brinjal is one of the most important Solanaceous crop cultivated widely throughout the country. The dark purple coloured fruit is preferred by consumer due to high anthocyanin content. The degree of pigmentation is unstable, possibly due to influence of environment, growth stage of fruit, etc. The present investigation was carried out to know the genetics of fruit colour and also to identify SSR marker linked to the trait. Cross was successfully attempted between Pusa Safed Baingan 1 (white coloured fruit) × Pusa Uttam (dark purple coloured fruit) to develop F1. A single F1 plant was selfed to develop 168 F2 plants and also backcross (36 BC1P1, 33 BC1P2) progenies developed. The skin colour of parents, F1, backcross and F2 plants was evaluated at edible maturity stage and compared with RHS colour chart. Bulk segregant analysis (BSA) was carried out to identify SSR marker linked to the gene for fruit skin colour. Segregation of fruit colour was analyzed by Chi square (ë2) test for goodness of fit. The fruit of F1 plants was intermediate revealed incomplete dominance. Out of 168 F2 plants, 125 were purple coloured, 31 green and 12 white which clearly segregated into 12:3:1 (P:G:W) ratio suggesting dominant epistasis with ë2 value of 0.28 (P=0.80-0.90). The BC1P1 (Pusa Safed Baingan 1 backcrossed with F1) showed 15 purple coloured, 11 green coloured and 10 white coloured which segregated in 2:1:1 ratio. Among the 18 parental polymophic SSR markers, only one marker (emg21I17165/200) was found to be polymorphic in BSA. This marker is segregated in 1:2:1 ratio suggesting cosegregation and linked with the gene for fruit skin colour. The result will be very useful in designing breeding strategies for developing dark purple coloured variety in eggplant and also the identified SSR marker will be useful in marker assisted breeding.