1) Advance the introgression of Fov4 resistance from SA-3208 into the BAR 32-30 breeding line that is homozygous for Ren2,3 and Mi1,2 and highly resistant to both root-knot and reniform nematodes. Evaluate resistant lines (BC1 and F2) in Fov1 and Fov4 infested soils and fields. Stack the insect resistant trait caryophyllene alcohol into the Fov4 and nematode resistant lines. 2) Advance the introgression of Fov4 resistance from â¿¿Pima S-4â¿¿, â¿¿Pima S-6â¿¿, and â¿¿Seabrook Sea Island 12B-2â¿¿, and from Gossypium arboreum accession # 190 into the BAR 32-30 line. Identify and evaluate homozygous Fov4 resistant lines (BC5S2 or BC5S3) in field tests. Identify markers associated with resistance. 3) Advance the introgression of Fov4 resistance from triple species hybrids derived from G. arboretum (4 accessions), G. herbaceum, G. armourianum, G. turneri into the BAR32-30 line. Identify and evaluate homozygous Fov4 resistant lines (BC5S1), advance to BC5S2 levels and evaluate in field tests. 4) Characterize genetic variation, virulence, and nematode interactions of Fov1 and Fov4, and elucidate virulence determinants and host resistance mechanisms through differential expression and functional genomic approaches.