Identification of QTLs for resistance to leaf and stem rusts in bread wheat (Triticum aestivum L.) using a mapping population of ‘Pamyati Azieva × Paragon’

Y Genievskaya,S Griffiths,S Abugalieva,Y Fedorenko,A Sarbayev,Y Turuspekov,A Amalova

doi:10.18699/vj19.563

Abstract

Leaf rust (LR) and stem rust (SR) are harmful fungal diseases of bread wheat (Triticum aestivum L.). The purpose of this study was to identify QTLs for resistance to LR and SR that are effective in two wheat-growing regions of Kazakhstan. To accomplish this task, a population of recombinant inbred lines (RILs) of ‘Pamyati Azieva × Paragon’ was grown in the northern and southeastern parts of Kazakhstan, phenotyped for LR/SR severities, and analyzed for key yield components. The study revealed a negative correlation between disease severity and plant productivity in both areas. The mapping population was genotyped using a 20,000 Illumina SNP array. A total of 4595 polymorphic SNP markers were further selected for linkage analysis after filtering based on missing data percentage and segregation distortion. Windows QTL Cartographer was applied to identify QTLs associated with LR and SR resistances in the RIL mapping population studied. Two QTLs for LR resistance and eight for SR resistance were found in the north, and the genetic positions of eight of them have matched the positions of the known Lr and Sr genes, while two QTLs for SR were novel. In the southeast, eight QTLs for LR and one for SR were identified in total. The study is an initial step of the genetic mapping of LR and SR resistance loci of bread wheat in Kazakhstan. Field trials in two areas of the country and the genotyping of the selected mapping population have allowed identification of key QTLs that will be effective in regional breeding projects for better bread wheat productivity.

Highlights

Wheat is one of the most important cereal crops in the World and Kazakhstan
The mapping population (MP) consisted of 98 recombinant inbred lines (RILs) and analyzed by using 4595 polymorphic SNP markers densely populated all 21 wheat chromosomes
Field trials output suggested a negative correlation between Leaf rust (LR) and stem rust (SR) severity and key yield components in the North and South-East regions of Kazakhstan

Summary

Introduction

Wheat is one of the most important cereal crops in the World and Kazakhstan (http://www.fao.org). An annual infection of bread wheat by fungal diseases is causing a serious yield reduction (Koyshybaev et al, 2017). The three most common wheat fungal pathogens in the world are Puccinia triticina Erikss. P. recondita is recognized as one of the most dangerous pathogens in wheat production worldwide, causing significant yield losses over the large geographical areas (Bolton et al, 2008). The infection with any rust fungus results in decreased numbers of kernels per spike and lower kernel weights due to the parasitic consumption of host nutrients, which leads to apparent yield losses and poor quality of the grains (Afzal et al, 2008)

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