Analyses of Fusarium wilt race 3 resistance in Upland cotton (Gossypium hirsutum L.)

Abstract

Fusarium wilt [Fusarium oxysporum f.sp. vasinfectum (FOV) Atk. Sny & Hans] represents a serious threat to cotton (Gossypium spp.) production. For the last few decades, the FOV pathogen has become a significant problem in Uzbekistan causing severe wilt disease and yield losses of G. hirsutum L. cultivars. We present the first genetic analyses of FOV race 3 resistance on Uzbek Cotton Germplasm with a series of field and greenhouse artificial inoculation-evaluations and inheritance studies. The field experiments were conducted in two different sites: the experimental station in Zangiota region-Environment (Env) 1 and the Institute of Cotton Breeding (Env-2, Tashkent province). The Env-1 was known to be free of FOV while the Env-2 was known to be a heavily FOV infested soil. In both (Env-1 and Env-2) of these sites, field soil was inoculated with FOV race 3. F2 and an F3 Upland populations ("Mebane B1" × "11970") were observed with a large phenotypic variance for plant survival and FOV disease severity within populations and among control or check Upland accessions. Wilt symptoms among studied F2 individuals and F3 families significantly differed depending on test type and evaluation site. Distribution of Mendelian rations of susceptible (S) and resistant (R) phenotypes were 1S:1R field Env-1 and 3S:1R field Env-2 in the F2 population, and 1S:3R greenhouse site in the F3 population. The different segregation distribution of the Uzbek populations may be explained by differences in FOV inoculum level and environmental conditions during assays. However, genetic analysis indicated a recessive single gene action under high inoculum levels or disease pressure for FOV race 3 resistance. Uzbek germplasm may be more susceptible than expected to FOV race 3, and sources of resistance to FOV may be limited under the FOV inoculum levels present in highly-infested fields making the breeding process more complex.

RNA Interference for Functional Genomics and Improvement of Cotton (Gossypium sp.)

“…Very limited information is available on RNAi directed studies in understanding the resistance of Fusarium oxysporum (FOV) wilting pathogen that has been a serious threat to cotton production across the world ( Abdullaev et al, 2015 ). With the target to develop novel RNAi-based cotton cultivars against FOV, Shapulatov et al (2015) recently characterized a “top-layer” of small RNA/miRNA profile in FOV race 3 infected versus uninfected cotton seedlings of resistant and susceptible cotton genotypes.…”

Interactions between cotton genotypes and Fusarium wilt race 4 isolates from Texas and resistance evaluation in cotton

“…W. C. Snyder and H. N. Hansen, FOV] (Cianchetta & Davis, 2015). Fusarium wilt is one of the most destructive diseases of cotton in the United States and other cotton‐growing countries including Brazil, China, India, Egypt, Uzbekistan, and Australia (Abdullaev et al., 2015; Crutcher et al., 2016; Zhang et al., 2015). Fusarium wilt of cotton was first reported in the southern United States in 1892 (Atkinson, 1892).…”

Recent studies on Fusarium wilt in cotton

“…Research has also explored FOV race 3 resistances in Uzbek cotton germplasm, and genetic analyses indicated that FOV resistance is primarily influenced by a recessive single-gene action under high inoculum levels or disease pressure [77]. These complexities were evident in differing segregation distributions of susceptible and resistant phenotypes among Uzbek populations.…”