Trichothecene-mediated in vitro selection in wheat for reduced mycotoxin accumulation caused by Fusarium graminearum

Abstract

Trichothecene, a factor of aggressiveness of Fusarium graminearum in wheat fusarium head blight (FHB), was evaluated in an anther co-culture assay for the regeneration of doubled haploid (DH) lines with reduced mycotoxin accumulation. A Fusarium graminearum culture filtrate and a defined mixture of purified trichothecenes were compared with a control treatment in two F1-derived microspores populations. Frontana and Katepwa were the FHB resistant and intermediate resistant sources, respectively, and the cultivar Norseman was the FHB susceptible parent. A preliminary evaluation of the subpopulations of DH lines, using the point inoculation method in the greenhouse, showed selection effects for FHB resistance in the trichothecene co-cultured Frontana/Norseman subpopulation only. Three years of field evaluation using the spray inoculation method revealed that the DH subpopulation from the F1 hybrid Frontana/Norseman co-culture in the presence of trichothecenes accumulated consistently less deoxynivalenol (DON) in the grain than the control subpopulation. The FHB symptoms were also significantly reduced for 1 yr (2001) in the same subpopulation. This subpopulation showed increased test weight, plant height and a 1.1-d delay in heading date when compared with the control subpopulation, under disease pressure. A trichothecene co-cultured DH subpopulation from Katepwa/Norseman also had a significantly lower DON content for 1 yr. Key words: Androgenesis, disease resistance, Gibberella zeae, mycotoxin, Triticum aestivum, wheat scab