title: Inheritance and QTL mapping of Fusarium wilt race 4 resistance in cotton.
abstract: Diseases such as Fusarium wilt [Fusarium oxysporum f.sp. vasinfectum (FOV) Atk. Sny & Hans] represent expanding threats to cotton production. Integrating disease resistance into high-yielding, high-fiber quality cotton (Gossypium spp.) cultivars is one of the most important objectives in cotton breeding programs worldwide. In this study, we conducted a comprehensive analysis of gene action in cotton governing FOV race 4 resistance by combining conventional inheritance and quantitative trait loci (QTL) mapping with molecular markers. A set of diverse cotton populations was generated from crosses encompassing multiple genetic backgrounds. FOV race 4 resistance was investigated using seven parents and their derived populations: three intraspecific (G. hirsutum × G. hirsutum L. and G. barbadense × G. barbadense L.) F1 and F2; five interspecific (G. hirsutum × G. barbadense) F1 and F2; and one RIL. Parents and populations were evaluated for disease severity index (DSI) of leaves, and vascular stem and root staining (VRS) in four greenhouse and two field experiments. Initially, a single resistance gene (Fov4) model was observed in F2 populations based on inheritance of phenotypes. This single Fov4 gene had a major dominant gene action and conferred resistance to FOV race 4 in Pima-S6. The Fov4 gene appears to be located near a genome region on chromosome 14 marked with a QTL Fov4-C14 1 , which made the biggest contribution to the FOV race 4 resistance of the generated F2 progeny. Additional genetic and QTL analyses also identified a set of 11 SSR markers that indicated the involvement of more than one gene and gene interactions across six linkage groups/chromosomes (3, 6, 8, 14, 17, and 25) in the inheritance of FOV race 4 resistance. QTLs detected with minor effects in these populations explained 5-19 % of the DSI or VRS variation. Identified SSR markers for the resistance QTLs with major and minor effects will facilitate for the first time marker-assisted selection for the introgression of FOV race 4 resistance into elite cultivars during the breeding process.
authors.affiliation: Cropping Systems Research Laboratory, Plant Stress and Germplasm Development Research, USDA-ARS, SPA, 3810 4th Street, Lubbock, TX 79415, USA. mauricio.ulloa@ars.usda.gov
authors.forename: Mauricio
authors.initials: M
authors.lastname: Ulloa
authors.forename: Robert B
authors.initials: RB
authors.lastname: Hutmacher
authors.forename: Philip A
authors.initials: PA
authors.lastname: Roberts
authors.forename: Steven D
authors.initials: SD
authors.lastname: Wright
authors.forename: Robert L
authors.initials: RL
authors.lastname: Nichols
authors.forename: R
authors.initials: R
authors.lastname: Michael Davis
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics*; D005670:Fusarium / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D017343:Genes, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D003368:Gossypium / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D007113:Immunity, Innate / Q000235:genetics*; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D040641:Quantitative Trait Loci
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers