Inheritance and linkage of a gene for resistance to race 4 of Fusarium wilt and RAPD markers in chickpea

Several races of Fusarium oxysporum Schlechtend.:Fr f. sp. ciceris (Padwick) Matuo and K. Sate cause economic losses from wilting disease of chickpea (Cicer arietinum L.). While the genetics of resistance to race 1 have been reported, little is known of the genetics of resistance to race 4. We undertook a study to determine the inheritance of resistance and identified random amplified polymorphic DNA markers (RAPDs) linked to the gene for resistance. For the investigation, we used 100 F-5 derived F-7 recombinant inbred lines (RILs) that had been developed from the cross of breeding lines C-104 x WR-315. Results indicated that resistance is controlled by a single recessive gene. The RAPD markers previously shown to amplify fragments linked to race 1 resistance also amplified fragments associated with race 4 resistance. The RAPD loci, CS-27(700), UBC-170(550) and the gene for resistance to race 4 segregated in 1:1 ratios expected for single genes. Both RAPD markers were located 9 map units from the race 4 resistance locus and were on the same side of the resistance gene. Our results indicated that the genes for resistance to race 1 and 4 are 5 map units apart. The need to determine the genomic locations of race specific resistance genes and the possibility that these genes are clustered to the same genomic region should be investigated.