FUSARIUM WILT OF COTTON: PATHOGEN POPULATION CHARACTERIZATION, VIRULENCE/ RESISTANCE MECHANISM DETERMINATION & MARKER ASSISTED RESISTANCE BREEDING

1.Characterize genetic variation, virulence, and nematode interactions of F. oxysporum isolates. 2. Advance and evaluate tolerance to FOV4 from ¿Pima S-2¿, ¿Pima S-4¿, ¿Pima S-6¿, ¿Sakel¿, ¿Seabrook Sea Island 12B-2¿, and Gossypium arboreum accession #190 into BAR 32 lines that are homozygous for Ren2,3 and Mi1,2 and are highly resistant to both root-knot and reniform nematodes. Identify markers associated with resistance. 3. Identify FOV4 virulence genes affected by transposon ¿Tfo1¿ and other mutator-like elements, and confirm the virulence role of the identified gene by gene knock-outs subsequent pathogenicity assays with knock-outs. 4. Determine the importance of fusaric acid in virulence and competition with antagonists using pathogenicity assays of various knock-out mutants in root rot pathotype isolates of Fov race 4 and Australian biotype.