Identification and mapping of leaf, stem and stripe rust resistance quantitative trait loci and their interactions in durum wheat

A Singh,H S Randhawa,R D Cuthbert,F R Clarke,A K Singh,K Ammar,M P Pandey,R P Singh,C J Pozniak,R M Depauw,J M Clarke,R E Knox,B D Mccallum,T G Fetch

doi:10.1007/s11032-012-9798-4

Abstract

Leaf rust (Puccinia triticina Eriks.), stripe rust (Puccinia striiformis f. tritici Eriks.) and stem rust (Puccinia graminis f. sp. tritici) cause major production losses in durum wheat (Triticum turgidum L. var. durum). The objective of this research was to identify and map leaf, stripe and stem rust resistance loci from the French cultivar Sachem and Canadian cultivar Strongfield. A doubled haploid population from Sachem/Strongfield and parents were phenotyped for seedling reaction to leaf rust races BBG/BN and BBG/BP and adult plant response was determined in three field rust nurseries near El Batan, Obregon and Toluca, Mexico. Stripe rust response was recorded in 2009 and 2011 nurseries near Toluca and near Njoro, Kenya in 2010. Response to stem rust was recorded in field nurseries near Njoro, Kenya, in 2010 and 2011. Sachem was resistant to leaf, stripe and stem rust. A major leaf rust quantitative trait locus (QTL) was identified on chromosome 7B at Xgwm146 in Sachem. In the same region on 7B, a stripe rust QTL was identified in Strongfield. Leaf and stripe rust QTL around DArT marker wPt3451 were identified on chromosome 1B. On chromosome 2B, a significant leaf rust QTL was detected conferred by Strongfield, and at the same QTL, a Yr gene derived from Sachem conferred resistance. Significant stem rust resistance QTL were detected on chromosome 4B. Consistent interactions among loci for resistance to each rust type across nurseries were detected, especially for leaf rust QTL on 7B. Sachem and Strongfield offer useful sources of rust resistance genes for durum rust breeding.

Highlights

Durum wheat (Triticum turgidum L. var. durum) is an important food crop traded in the international market for use in pasta and couscous production
We identified that the durum wheat cultivar Sachem was resistant while Strongfield, the predominant cultivar grown on the Canadian prairies, was moderately susceptible to the BBG/BN leaf rust race and Ug99 stem rust races
The parents and doubled haploid (DH) lines were evaluated for reaction to leaf rust in field nurseries operated by CIMMYT in Mexico near El Batan in 2009, Toluca in 2009 and 2011, and Obregon in 2010

Summary

Introduction

Durum wheat (Triticum turgidum L. var. durum) is an important food crop traded in the international market for use in pasta and couscous production. Recent leaf rust epidemics on durum wheat in Mexico (2001–2009) caused significant economic impact, with a total loss estimated at about US$72 million (Huerta-Espino et al 2011; Singh et al 2004). The novel virulent leaf rust race BBG/ BN and its variant BBG/BP overcame the resistance of widely adapted durum cultivars in North-western Mexico which had been effective and stable for more than 25 years (Huerta-Espino et al 2009a, b; Singh et al 2004). These virulent races pose a serious threat to durum cultivars of the USA and Canada because these races may spread through the North American rust corridor. This necessitates identification of sources of leaf rust resistance that can be bred into Canadian durum wheat

Objectives

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Conclusion