Genome-wide association study of yield components in spring wheat collection harvested under two water regimes in Northern Kazakhstan.

Akerke Amalova,Adylkhan Babkenov,Yerlan Turuspekov,Saule Abugalieva,Sandukash Babkenova

doi:10.7717/peerj.11857

Abstract

BackgroundBread wheat is the most important cereal in Kazakhstan, where it is grown on over 12 million hectares. One of the major constraints affecting wheat grain yield is drought due to the limited water supply. Hence, the development of drought-resistant cultivars is critical for ensuring food security in this country. Therefore, identifying quantitative trait loci (QTLs) associated with drought tolerance as an essential step in modern breeding activities, which rely on a marker-assisted selection approach.MethodsA collection of 179 spring wheat accessions was tested under irrigated and rainfed conditions in Northern Kazakhstan over three years (2018, 2019, and 2020), during which data was collected on nine traits: heading date (HD), seed maturity date (SMD), plant height (PH), peduncle length (PL), number of productive spikes (NPS), spike length (SL), number of kernels per spike (NKS), thousand kernel weight (TKW), and kernels yield per m2 (YM2). The collection was genotyped using a 20,000 (20K) Illumina iSelect SNP array, and 8,662 polymorphic SNP markers were selected for a genome-wide association study (GWAS) to identify QTLs for targeted agronomic traits.ResultsOut of the total of 237 discovered QTLs, 50 were identified as being stable QTLs for irrigated and rainfed conditions in the Akmola region, Northern Kazakhstan; the identified QTLs were associated with all the studied traits except PH. The results indicate that nine QTLs for HD and 11 QTLs for SMD are presumably novel genetic factors identified in the irrigated and rainfed conditions of Northern Kazakhstan. The identified SNP markers of the QTLs for targeted traits in rainfed conditions can be applied to develop new competitive spring wheat cultivars in arid zones using a marker-assisted selection approach.

Highlights

Bread wheat (Triticum aestivum L.) is the most important cereal crop in Kazakhstan, where it is grown on over 12 million hectares
The Finlay and Wilkinson (FW) regression analysis (Fig. 1B) suggested that the yield per m2 (YM2) of four wheat accessions, WS10, WS32, WS82, and WS85, was stable in all three tested years (2018, 2019 and 2020) out of the nine accessions highlighted in the box in Fig. 1A, showing YM2 values of 400 g/m2 and higher
The collection of spring wheat consisting of 179 local cultivars and promising lines showed a wide range of grain yield under two water regimes in the Akmola region of northern Kazakhstan in 2018, 2019 and 2020

Summary

Introduction

Bread wheat (Triticum aestivum L.) is the most important cereal crop in Kazakhstan, where it is grown on over 12 million hectares. Drought has a significant influence on the physiological functions wheat, such as in prompting stomatal closure, decreased photosynthesis, the development of oxidative stress, and the production of toxic metabolites (Bray, 2002) These changes in plant physiology lead to decreased plant height, reduced total shoot length, diminished growth rates, decreased number of tillers, reduced relative water content (Nezhadahmadi, Prodhan & Faruq, 2013), a decline in various grain quality parameters (Tsenov et al, 2015) and, substantial yield losses (Zhang et al, 2018). The identified SNP markers of the QTLs for targeted traits in rainfed conditions can be applied to develop new competitive spring wheat cultivars in arid zones using a markerassisted selection approach

Methods

Results

Discussion

Conclusion