Quantitative trait loci analysis of adult plant resistance to Parastagonospora nodorum blotch in winter wheat cv. Liwilla (Triticum aestivum L.)

Abstract

Parastagonospora nodorum leaf and glume blotch (syn. Septoria nodorum blotch, SNB) is a severe disease in many wheat-growing areas worldwide. In a previous study, a mapping population, Liwilla × Begra, was used to detect several resistance quantitative trait loci (QTL) at the seedling stage. In this study the same mapping population was analysed at the adult plant stage under field and polytunnel conditions. After artificial inoculation the disease severity on leaves and glumes was scored as the areas under the disease progress curves for field tests and as the percentage of the leaf and glume area covered by necrosis for the polytunnel test. Three QTL associated with Septoria nodorum glume blotch resistance and two QTL associated with Septoria nodorum leaf blotch resistance were detected on chromosomes 1B, 3A, 4A and 7D. Each of the detected QTL explained only a small proportion of the total phenotypic variation, ranging from 9.1 to 20.0%. None of these QTL co-located with necrotrophic effector sensitivity loci or aligned with previously identified resistance loci at the seedling stage for the Liwilla × Begra population. SNB resistance QTL detected in our study did not overlap with QTL associated with morphological and developmental traits. Therefore they could be involved in the defence reaction and can be considered in wheat improvement for SNB resistance.

Identification and cross-validation of genetic loci conferring resistance to Septoria nodorum blotch using a German multi-founder winter wheat population

“…Subsequent reduction of the ToxA sensitive wheat growing area by 13.5% between 2009 and 2013 was estimated to have saved 50 million $ in crop losses (Vleeshouwers and Oliver 2014 ). Genetic studies have identified numerous additional SNB resistance QTLs at the juvenile or the adult plant stages (reviewed most recently by Ruud and Lillemo 2018 , with additional QTL identified in subsequent studies by Czembor et al 2019 ; Francki et al 2020 ; Hu et al 2019 ; Lin et al 2020a ; Ruud et al 2019 ), including many that have not been associated with genetic loci controlling effector sensitivity. Taken together, these map to 20 of the 21 wheat chromosomes.…”

Evaluation of Septoria nodorum blotch (SNB) resistance in glumes of wheat (Triticum aestivum L.) in multiple field environments and the genetic relationship with foliar disease response

“…There is increasing evidence that disease response to glume and foliar SNB in the eld is controlled by many independent and mostly environmental-speci c QTL (Czembor et al 2019;Francki et al 2020;Lin et al 2020;Ruud and Lillemo, 2018;Ruud et al, 2019) exacerbating the complexity of genetic resistance and susceptibility to SNB in wheat. The majority of the QTL detected for either glume or foliar response to SNB in this study were detected at one location but not another, con rming the inherent and convoluted genetic mechanisms for resistance and susceptibility in eld assessment.…”

“…Moreover, morphological characteristics can have a profound effect on disease response so it is important to discriminate between pleiotropy and linkage with resistance in genetic analysis (Francki, 2013). There have been at least 20 QTL associated with glume resistance identi ed across the wheat genome with each accounting for up to 24% of the phenotypic variation indicating small effects on resistance phenotypes (Czembor et al 2019;Lin et al 2020;Schnurbusch et al 2003;Shankar et al 2008;Uphaus et al 2007). Similarly, at least 18 QTL have been identi ed for foliar resistance (reviewed in Francki, 2013;Ruud and Lillemo, 2018) with subsequent reports of others that may represent existing or, indeed, new QTL (Czembor et al 2019;Ruud et al 2019;Francki et al 2020;Lin et al 2020).…”

“…There have been at least 20 QTL associated with glume resistance identi ed across the wheat genome with each accounting for up to 24% of the phenotypic variation indicating small effects on resistance phenotypes (Czembor et al 2019;Lin et al 2020;Schnurbusch et al 2003;Shankar et al 2008;Uphaus et al 2007). Similarly, at least 18 QTL have been identi ed for foliar resistance (reviewed in Francki, 2013;Ruud and Lillemo, 2018) with subsequent reports of others that may represent existing or, indeed, new QTL (Czembor et al 2019;Ruud et al 2019;Francki et al 2020;Lin et al 2020). Recent quantitative genetic analysis detected QTL for either glume or foliar SNB response in different eld environments whereby some shared the same marker interval (Schnurbusch et al 2003;Lin et al 2020) indicating similar genes may have an effect on disease resistance or susceptibility in both organs.…”

Evaluation of Pyrenophora tritici-repentis Infection of Wheat Heads

“…While a significant body of work has focused on plant host resistance to foliar diseases, the inheritance of resistance to grain disease is a less explored topic. Several wheat genetic studies have been published with the aim to improve the resistance of breeding lines to black point [29][30][31][32] and wheat spike diseases [33][34][35][36][37][38]. However, the complexity of studying grain infection is often exacerbated with the influence of foliar disease on the host.…”