A second gene for resistance to race 4 of Fusarium wilt in chickpea and linkage with a RAPD marker

Fusarium wilt caused by Fusarium oxysporum Schlechtend.: Fr f. sp. ciceris (Padwick) Matuo & Sato is a devastating disease of chickpea. The current st udy was conducted to determine the inheritance of the gene(s) for resistanc e to race 4 of fusarium wilt and to identify linked RAPD markers using an e arly wilting line, JG-62, as a susceptible parent. Genetic analysis was per formed on the F(1)s, F(2)s and F-3 families from the cross of JG-62 x Surut ato-77. The F-3 families were inoculated with a spore suspension of the rac e 4 wilt pathogen and the results were used to infer the genotypes of the p arent F-2 plants. Results indicated that two independent genes controlled r esistance to race 4. Linkage analysis of candidate RAPD marker, CS-27(700), and the inferred F-2 phenotypic data showed that this marker locus is link ed to one of the resistance genes. Allelism indicated that the two resistan ce sources, Surutato-77 and WR-315, shared common alleles for resistance an d the two susceptible genotypes, C-104 and JG-62, carried alleles for susce ptibility. The PCR-based marker, CS-27(700), was previously reported to be linked to the gene for resistance to race 1 in a different population which suggested that the genes for resistance to races 1 and 4 are in close prox imity in the Cicer genome.