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

Wentao Zhang,Harpinder S Randhawa,Fengying Jiang,Brittany Polley,Zeinab Robleh Djama,François Eudes,Kerry Boyle,Pierre R Fobert,Peng Gao,Anita L Brûlé-Babel,George Fedak,Richard D Cuthbert

doi:10.3389/fpls.2020.580833

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.

Highlights

Fusarium head blight (FHB), or scab, mainly caused by the fungus Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schw. (Petch)], is the most serious fungal disease affecting bread and durum wheat production in Canada (Gilbert and Tekauz, 2000)
A better understanding of the genetic architecture underlying these different components may enable the development of wheat cultivars with better resistance to FHB
A systematic analysis of different components was undertaken with two large bi-parental mapping populations, revealing how different FHB resistance components, plant height and flowering time, interact

Summary

Introduction

Fusarium head blight (FHB), or scab, mainly caused by the fungus Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schw. (Petch)], is the most serious fungal disease affecting bread and durum wheat production in Canada (Gilbert and Tekauz, 2000). (Petch)], is the most serious fungal disease affecting bread and durum wheat production in Canada (Gilbert and Tekauz, 2000). The lighter weight of FDKs and the high level of FDKs within a commercial wheat crop result in severe yield and quality losses (Gilbert and Tekauz, 2000; McMullen et al, 2012). The disease has become a more serious threat to wheat production for farmers with trends toward Fusarium isolates that produce higher levels of DON and more frequent FHB outbreaks across the Western Canadian Prairies (Gilbert and Tekauz, 2000). Annual losses attributed to FHB in Canada are in the hundreds of millions of dollars (Haile et al, 2019)

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