Determination of resistance of different types of melon genotypes to Fusarium oxysporum f. sp. melonis by classic and molecular methods

Fusarium wilt caused by soil-borne pathogen Fusarium oxysporum f. sp. melonis (FOM) is one of the most important fungal diseases limiting melon production in the world. The disease occurs in 85% of the melon growing areas of our country. Four different races of the fungus (0, 1, 2 and 1-2) have been recognized in melon fileds so far. Chemical fungicides have been heavily used to control the disease in the field. However, the most effective and environmentally friendly approach is the identification and employment of melon varieties or genotypes resistant to the disease. This thesis research was designed to determine the resistance status of 20 different genotypes derived from Kırkağaç, Galia, Ananas and Piel de Sapo melon types to the race 1 and 2 of F. oxysporum f. sp. melonis in classical and molecular assays. A total of 12 melon seedlings from each genotypes representing 3 replicates were included in each of the two consecutive classical trials conducted by using the seedling root dipping method. In molecular assays, SSR154/ Fom2-R408 markers and NBS1-CAPS, Fom1-R/Fom1-S markers were used to determine the resistance of the genotypes to the race 1 and race 2 of the fungus respectively. Out of 20 genotypes tested, 11 genotypes were found to be resistant to race 1, 7 genotypes to race 2, and 4 genotypes to both race 1 and race 2 in classical assays. In molecular assays with SSR154 marker, 10 genotypes were determined as resistant to the race 1 of the fungus. Overall results clearly indicated that molecular assays using SSR154 marker was in parallel with the classical inoculation assays.