Genetic Characterization of Multiple Components Contributing to Fusarium Head Blight Resistance of FL62R1, a Canadian Bread Wheat Developed Using Systemic Breeding

Abstract

Fusarium head blight (FHB) is a devastating fungal disease of small-grain cereals that results in severe yield and quality losses. FHB resistance is controlled by resistance components including incidence, field severity, visual rating index, Fusarium damaged kernels (FDKs), and the accumulation of the mycotoxin deoxynivalenol (DON). Resistance conferred by each of these components is partial and must be combined to achieve resistance sufficient to protect wheat from yield losses. In this study, two biparental mapping populations were analyzed in Canadian FHB nurseries and quantitative trait loci (QTL) mapped for the traits listed above. Nine genomic loci, on 2AS, 2BS, 3BS, 4AS, 4AL, 4BS, 5AS, 5AL, and 5BL, were enriched for the majority of the QTL controlling FHB resistance. The previously validated FHB resistance QTL on 3BS and 5AS affected resistance to severity, FDK, and DON in these populations. The remaining seven genomic loci colocalize with flowering time and/or plant height QTL. The QTL on 4B was a major contributor to all field resistance traits and plant height in the field. QTL on 4AL showed contrasting effects for FHB resistance between Eastern and Western Canada, indicating a local adapted resistance to FHB. In addition, we also found that the 2AS QTL contributed a major effect for DON, and the 2BS for FDK, while the 5AL conferred mainly effect for both FDK/DON. Results presented here provide insight into the genetic architecture underlying these resistant components and insight into how FHB resistance in wheat is controlled by a complex network of interactions between genes controlling flowering time, plant height, local adaption, and FHB resistance components.

Keywords: DON; Fusarium head blight; QTL; SNP; flowering; genetic architecture; resistance components.

FIGURE 1

Distribution of phenotypic traits from field trials in different years and locations. Fusarium damaged kernels (FDKs), incidence (INC), and severity (SEV) at (A) Carman, Manitoba (W) and (B) Ottawa, Ontario (O) trials; and (C) deoxynivalenol (DON) from all environments.

FIGURE 2

Phenotypic correlation between Fusarium head blight-resistance components and associated traits at two field locations for two populations. The areas of the circles show the absolute value of the corresponding correlation coefficients (r). INC, incidence; SEV, severity; FDK, Fusarium damaged kernels; DON, deoxynivalenol; HT, plant height; DA, day to anthesis; O, Ottawa, Ontario; W, Carman, Manitoba. 15, 2015; 16, 2016; ST, Stettler population; MM, Muchmore population.

FIGURE 3

QTLs of Fusarium head blight resistance, flower time, and plant height anchored on the Chinese Spring reference 1.0 (CS Ref 1.0). The marker located at the peak of the QTL identified by blast on CS Ref 1.0 was used to localize QTL. INC, incidence; SEV, severity; FDK, Fusarium damaged kernels; DON, deoxynivalenol; HT, plant height; DA, day to anthesis; O, Ottawa, Ontario; W, Carman, Manitoba.