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Inheritance and genetic linkage of fusarium wilt {Fusarium oxysporum f.sp. cucumerinum race 1) and scab {Cladosporium cucumerinum) resistance genes in cucumber (Cucumis sativus)
Author(s) -
VAKALOUNAKIS D J
Publication year - 1993
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1993.tb04098.x
Subject(s) - biology , cucumis , fusarium wilt , fusarium oxysporum , cucurbitaceae , botany , locus (genetics) , plant disease resistance , seedling , cultivar , cotyledon , horticulture , gene , genetics
Summary The inheritance of resistance of the cucumber cv. SMR 18 to the race 1 of Fusarium oxysporum f.sp. cucumerinum, the linkage relationship between resistance to race 1 of F. oxysporum f.sp. cucumerinum, resistance to Cladosporium cucumerinum and fruit spine colour, and the reactions of several cucumber cultivars to inoculations with race 1 of F. oxysporum f.sp. cucumerinum and C. cucumerinum were examined. The inbred line Straight 8 (P,), which has white fruit spines and is susceptible to both fusarium wilt and scab was crossed with the inbred line SMR 18 (P 2 ), which has black fruit spines and resistance to both diseases. When F, F 2 , F 3 , BC 1 P 1 BC 1 P 2 and BC 1 P 1 selfed progenies were inoculated at the cotyledon stage with a suspension of spores of race 1 of F. oxysporum f.sp. cucumerinum, the ratios of resistant to susceptible plants indicated that resistance was conferred by a single dominant gene, designated Fcu‐1. When 171 BC^! plants were selfed and from each resulting F 2 family different groups of 15–25 seedlings each were tested for resistance to either disease, segregation data indicated that the Fcu‐1 locus and the Ccu locus for C. cucumerinum resistance were completely linked. No evidence for linkage was found between the Fcu‐1 (Ccu) locus and the B locus for fruit spine colour. Among the 59 cultivars tested at the seedling stage, 15 were susceptible, while the remainder were highly resistant to inoculations with both pathogens.