Title : QTL mapping for adult-plant resistance to leaf rust in Italian wheat cultivar libellula
Abstract:
Wheat leaf rust (Lr), which is caused by Puccinia triticina Eriks. (Pt) is one of the most important wheat diseases affecting wheat production globally. Using resistant wheat cultivars is the most economical and environmentally friendly way to control leaf rust. The Italian wheat cultivar Libellula has demonstrated good resistance to Lr in field studies. In order to identify the genetic basis of Lr resistance in Libellula, 248 F6 recombinant inbred lines from the cross Libellula/Huixianhong was phenotyped for Lr severity in seven environments: the 2014/2015, 2016/2017, 2017/2018, and 2018/2019 cropping seasons at Baoding, Hebei Province and the 2016/2017, 2017/2018, and 2018/2019 crop seasons at Zhoukou, Henan Province. Bulked segregant analysis and simple sequence repeat markers were then used to identify the quantitative trait loci (QTLs) for Lr adult-plant resistance in the population. Six QTLs were consequently detected, designated as QLr.hebau-1AL and QLr.hebau-1AS presumed to be new, QLr.hebau-1BL, QLr.hebau-3AL, QLr.hebau-4BL, and QLr.hebau-7DS identified at similar physical positions as previously reported QTLs. Based on chromosome positions and molecular marker tests, QLr.hebau-1BL and QLr.hebau-7DS share similar flanking markers with Lr46 and Lr34, respectively. Lr46 and Lr34 are race non-specific APR genes for leaf rust, stripe rust, and powdery mildew. Similarly, QLr.hebau-4BL showed multiple disease resistance to leaf rust, stripe rust, fusarium head blight, and powdery mildew. The QTL identified in this study, as well as their closely linked markers, may potentially be used in marker-assisted selection in wheat breeding.
