Genomic predictions for Fusarium head blight resistance in a diverse durum wheat panel: an effective incorporation of plant height and heading date as covariates

Jose Moreno-Amores,Hermann Buerstmayr,C Friedrich H Longin,Thomas Miedaner,Sebastian Michel

doi:10.1007/s10681-019-2551-x

Jose Moreno-Amores, Hermann Buerstmayr + Show 3 more

Open Access

https://doi.org/10.1007/s10681-019-2551-x

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Abstract

Selection for multiple traits is a highly challenging task for breeders due to potential unfavorable associations between characters. Fusarium head blight FHB, being one of the most relevant diseases affecting durum wheat frequently shows in this respect an unfavorable correlation with morpho-agronomical traits like plant height (PH) and heading date (HD). In this study, we used a cross-validation scheme to assess the prediction ability of the genomic predictions (GP) for FHB severity relying on genomic best linear unbiased prediction models in a diverse panel of 178 durum wheat lines evaluated across five environments. Additionally, we compared three types of approaches to include HD and PH as covariates into the analysis: (1) correcting FHB severity values before training GP models, (2) tuning the GP model parameters that included multi-trait alternatives, and (3) adjusting the genomic-based predictions by restriction indexes. Models that weighted genomic estimated breeding values (GEBV) by restriction indexes as well as models that predicted FHBms values corrected by regression-based methods were efficient alternatives in diminishing the HD trade-off, nonetheless they were also associated with large reductions in prediction ability for FHB severity. After a simulated round of genomic selection, considering HD as fixed effect in the GP model were the most suitable alternative to select a higher proportion of genotypes moderately resistant with lower-than-average HD and PH estimations. Hence, an appropriate GP model given unfavorable association between characters should combine high predictabilities and adequate reduction of undesired trade-offs.

Highlights

Fusarium head blight FHB, called scab, is one of the most calamitous diseases affecting cereals such as wheat, barley, maize and oat (Walter et al 2010; Beres et al 2018)
In the second method, denoted as ADJ.B, we investigated the approach suggested by Emrich et al (2008), Miedaner et al (2006), and included plant height and heading date as fixed covariates when calculating Best Linear Unbiased Estimates (BLUE) resulting in an extension of model (1) to: yikm 1⁄4 l þ gi þ rk þ bm þ bHDc1ikm þ bPH c2ikm þ eikm ð4Þ
Such allele combination and deployment in durum populations has been typically achieved by phenotypic selection or Marker assisted selection (MAS) in the past, genomic selection might nowadays be prefigured as a recommended strategy to capture the genetic variation generated by many small-effect QTL and might assist breeders by shortening the breeding cycle or improve the selection gain in early stages where typically more resistant lines could in this way be selected

Summary

Introduction

Fusarium head blight FHB, called scab, is one of the most calamitous diseases affecting cereals such as wheat, barley, maize and oat (Walter et al 2010; Beres et al 2018). Durum wheat is a cereal crop with an annual global production of 39 million of tons corresponding to 5% of the total wheat production (Kadkol and Sissons 2016). Other essential foodstuffs like couscous and pasta, consumed by hundreds millions people worldwide, are prepared based on semolina that is the granular milled product of durum grains (Fiedler et al 2017; Tuberosa and Pozniak 2014). Within a Genotype Â Environment Â Management (GÂEÂM) interaction framework, the development and adoption of cultivars tolerant to FHB is and will remain to be the cornerstone of any strategy aiming to manage this disease (Beres et al 2018)

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