Genetic analysis and tagging of gene controlling fruit tubercles and fruit ridgeness pattern in bitter gourd using SSR markers

Abstract

Thepresence of tubercles and pattern of ridges (continuous vs discontinuous) are important traits of bitter gourd which determine market price in India.The tuberculate fruits with broken or discontinuous ridges have more unit price than the non-tuberculate and continuous ridged fruits. In the present study, two different botanical varieties of Momordica charantia var. charantia (DBGS-2 and DBGS-54) and M. charantia var. muricata (DBGS-34) were used for inheritance study and molecular tagging of fruit tubercles and fruit ridgeness pattern. The findings revealed the monogenic control for both the traits. The bi-parental mapping populations (F2) were developed from the crosses DBGS-54×DBGS-34 and DBGS-2×DBGS- 34 for tagging of tuberculate (Tb) and continues ridgeness (cr) locus, using SSR markers. The single plant analysis of F2 population (derived from DBGS-54×DBGS-34) based on SSR markers found McSSR-20 was linked to fruit tubercles gene (Tb) at 12.50 cM and another SSR marker JY004 in the cross DBGS-2×DBGS-34 was found linked with fruit ridgeness pattern (cr) gene at a distance of 19.6cM. It is the first report of SSR markers linked to fruit tubercles and ridgeness which will be helpful further in fine mapping of these traits with more PCR based markers. These findings will help in differenciating the genotypes with tubercles and pattern of ridgeness at the early stage of the crop and can be used in accelerating trait specific breeding programme in bitter gourd.