Tagging and mapping a second resistance gene for Fusarium wilt race 0 in chickpea

A second gene conferring resistance to the chickpea wilt pathogen, Fusarium oxysporum f. sp ciceris race 0, has been mapped to linkage group 2 (LG2) of the chickpea genetic map. Resistance to race 0 is controlled by two genes which segregate independently; one present in accession JG62 (Foc0 1 /foc0 1 ) and mapping to LG5 and the second present in accession CA2139 (Foc0 2 /foc0 2 ) but remaining unmapped. Both genes separately confer complete resistance to race 0 of the wilt pathogen. Using a Recombinant Inbred Line (RIL) population that segregated for both genes (CA2139 × JG62) and the genotypic information provided by two markers flanking Foc0 1 /foc0 1 ten resistant lines containing the resistant allele Foc0 2 /foc0 2 were selected. Genotypic analysis using these ten resistant lines paired with ten susceptible RILs, selected in the same population, revealed that sequence tagged microsatellite sites (STMS) markers sited on LG2 were strongly associated with Foc0 2 /foc0 2 . Linkage analysis, using data from two mapping populations (CA2139/JG62 and CA2156/JG62), located Foc0 2 /foc0 2 in a region where genes for resistance to wilt races 1, 2, 3, 4 and 5 have previously been reported and which is highly saturated with tightly-linked STMS markers that could be used in marker-assisted selection (MAS).