Linkage mapping in a watermelon population segregating for fusarium wilt resistance

Abstract

Isozyme, randomly amplified polymorphic DNA (RAPD), and simple sequence repeats (SSR) markers were used to generate a linkage map in an F₂ and F₃ watermelon (Citrullus lanatus (Thumb.) Matsum. & Nakai) population derived from a cross between the fusarium wilt (Fusarium oxysporum f. sp. niveum) susceptible "New Hampshire Midget" and resistant PI 296341-FR. A 112.9 cM RAPD-based map consisting of 26 markers spanning two linkage groups was generated with F₂ data. With F₃ data, a 139 cM RAPD-based map consisting of 13 markers covering five linkage groups was constructed. Isozyme and SSR markers were unlinked. About 40 percent to 48 percent of the RAPD markers were significantly skewed from expected Mendelian segregation ratios in both generations. Bulked segregant analysis and single-factor analysis of variance were employed to identify RAPD markers linked to fusarium wilt caused by races 1 and 2 of F. oxysporum f. sp. niveum. Current linkage estimates between the resistance trait and the marker loci were too large for effective use in a marker-assisted selection program.

Citation

Hawkins, Leigh K.; Dane, Fenny; Kubisiak, Thomas L.; Rhodes, Billy B.; Jarret, Robert L. 2001. Linkage mapping in a watermelon population segregating for fusarium wilt resistance. Journal of American Society for Horticultural Science. 126(3): 344-350