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

Abstract

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.