Identification of AFLP markers linked to resistance of cowpea (Vigna unguiculata L.) to parasitism by Striga gesnerioides

• Published in: Theoretical and applied genetics 2001-05, Vol.102 (6-7), p.1029-1036
• Main Authors: OUEDRAOGO, J. T, MAHESHWARI, V, BERNER, D. K, ST-PIERRE, C.-A, BELZILE, F, TIMKO, M. P
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Classical genetics, quantitative genetics, hybrids; Cloning; Cultivars; Fundamental and applied biological sciences. Psychology; Genes; Genetics of eukaryotes. Biological and molecular evolution; Plant diseases; Pteridophyta, spermatophyta; Rsq2-1 gene; Segregation; Striga; Striga gesnerioides; Vegetals; Vigna; Vigna unguiculata
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s001220000499

AFLP and bulked segregant analysis were used to identify molecular markers linked to resistance of cowpea [Vigna ungiculata (L.) Walp.] to parasitism by Striga gesnerioides (Willd.) Vatke. Segregation analysis of F^sub 2^ progeny from a cross of Tvx3236, a Striga-susceptible line, with IT82D-849, a resistant cultivar, showed that resistance to S. gesnerioides race 1 from Burkina Faso was controlled by a single dominant gene, designated Rsg2-1. Three AFLP markers were identified that are tightly linked to Rsg2-1: E-AAC/M-CAA^sub 300^ (2.6 cM), E-ACT/M-CAA^sub 524^ (0.9 cM), and E-ACA/M-CAT^sub 140/150^ (0.9 cM), which appears to be codominant. Segregation analysis of a different F^sub 2^ population resulting from a cross of the Striga-susceptible line IT84S-2246-4 with Tvu 14676, a S. gesnerioides race 3 resistant line, showed that resistance to S. gesnerioides race 3 was also controlled by a single dominant gene, designated Rsg4-3. Six AFLP markers linked to Rsg4-3 were identified: E-ACA/M-CAG^sub 120^ (10.1 cM), E-AGC/M-CAT^sub 80^ (4.1 cM), E-ACA/M-CAT^sub 150^ (2.7 cM), E-AGC/M-CAT^sub 150^ (3.6 cM), E-AAC/M-CAA^sub 300^ (3.6 cM), and E-AGC/M-CAT^sub 70^ (5.1 cM). Segregation analysis of the E-AAC/M-CAA^sub 300^ and E-ACA/M-CAG^sub 120^ markers in recombinant inbred lines derived from IT84S-2049×524B determined that both are located within linkage group 1 of the cowpea genetic map. The identification of AFLP markers linked to Striga resistance provides a stepping stone for a marker-assisted selection program and the eventual cloning and characterization of the gene(s) encoding resistance to this noxious parasitic weed.[PUBLICATION ABSTRACT]