A molecular clue towards fusarium wilt resistant gene in melon (Cucumis melo L.) germplasm

Fusarium wilt [Fusarium oxysporum f. sp. melonis (Fom)], is one of the most serious diseases of muskmelon in India. Fifty accessions of muskmelon and its relatives collected from diverse sources were subjected to molecular screening with Fom1 and Fom2 gene specific markers. Presence of Fom1 (R) gene was confirmed using RG-9-2 marker where as susceptible allele was confirmed with another set of primer S-TAG/GCC-470. Out of 50 germplasm lines, 16 lines were found to be positive. Among which, eight were homozygous and eight were heterozygous in nature. The S-TAG/GCC- 470 could only able to confirm susceptible allele in exotic lines but was failed to confirm the same in Indian accessions. While for Fom2 gene, a combination of R-408 (R allele) and S-342 (S allele) were used. Six genotypes contained homozygous resistant gene while only three lines showed heterozygous nature for Fom2 gene. Only two genotypes viz., SM-2012-12 and IC-267359 contained both the resistant genes, whereas Kajri Sel.1, IC-267375, MM-314 and MM- 4305 contained Fom1 gene. These results conclude the presence of novel resistant gene in Indian melon gene pool and there is an opportunity for developing new gene based markers for these novel genes which will be useful to strengthen the resistance against newly evolving pathogenic races.