Breeding tomato (Lycopersicon esculantum) For resistance against different species of fusarium

Tomato Lycopersicon esculantum Mill. is one of the most important vegetable crop worldwide. In Sudan tomato is produced in different areas and winter is the best season for production. Lately, symptoms of wilt and lor root rot were observed in tomato fields and it's emerging as potential risk for tomato production in the Sudan. This Study was conducted during 2003-2006,to investigate the causal pathogen and breeding tomato for resistance. Surveys, collection of diseased tomato plants, isolation, identification of recovered Fusarium spp., and pathogenicity tests for all recovered Fusarium isolates were conducted during the course of this study. The results showed that Fusarium solani was the most prevailing Fusarium species recovered from diseased tomato plants collected from the Sudan. Species belongs to Gibbosum section came in the second position followed by species belongs to liseaola section. RAPD test was used to confirm the morphological identification of some Fusarium spp. Pathogenicity tests revealed that F. nygamai, F. cf. nygamai and F. pseudonygamai are pathogenic on tomato plants and they are the causal agent for root rot of tomato in Sudan. This is the first report for these species causing root rot disease on tomato plants. Cultivated commercial tomato varieties and farmer varieties were tested for resistance to the three known races of Fusarium oxysporum f. sp. lycopersici as well as the pathogenic Fusarium species recovered during the course of this study. The results revealed that most cultivars were susceptible to FOL race 2 and race 3, although some cultivars were resistant to FOL race 2 and all tested commercial varieties grown in Sudan were resistant to race 1 of FOL. Some HSD accessions showed resistance to F. nygamai, F. cf. nygamai and F. pseudonygamai and they could be used as base for breeding tomato for root rot resistance. Resistance to FOL race 3 was transferred to Omdurman and Strain B varieties while resistance to FOL race 2 was transferred to the variety Omdurman using the backcross method. Screening of F), BCI and Bcz of LA4065 with Omdurman and strain B confirmed that one single dominant gene is controlling the resistance character. Meanwhile, RGA332 Molecular marker proved to be a fast and powerful tool for screening for resistance to FOL race 3 controlled by 1-3 gene. Resistance to FOL race 2 was successfully transferred to Omdurman variety from LA4026