Genetic resistance to major fungal diseases of barley in Kazakhstan: advances, challenges, and breeding perspectives

Abstract

Abstract
Background and Aim. Barley (Hordeum vulgare L.) is a key cereal crop in Kazakhstan, ranking second after wheat and making a substantial contribution to livestock production and food security.
However, barley productivity is strongly constrained by major fungal diseases, including net blotch, barley scald, powdery mildew, and stem rust, causing yield losses of 10-40% and up to 100% under severe epidemics. This review summarizes current knowledge on the genetic basis of resistance to these diseases, with particular emphasis on resistance genes, quantitative trait loci (QTLs), and their
application in barley breeding in Kazakhstan.
Materials and Methods. The review is based on the analysis of published scientific literature and recent molecular studies, including genome-wide association studies (GWAS) and SSR-marker analyses conducted on globally diverse and locally adapted barley germplasm. Particular emphasis was placed on studies performed under the agroecological conditions of Kazakhstan.
Results. Numerous resistance loci associated with major barley diseases have been identified and characterized. In Kazakhstan, GWAS identified 59 QTLs for net blotch (25 novel), 7 QTLs for powdery mildew (5 novel), and 19 QTLs for stem rust (13 novel), along with validation of known resistance genes. These studies also confirmed the presence of both globally relevant and region-specific resistance sources in local germplasm. The findings highlight the importance of combining major resistance genes with quantitative resistance loci and adult plant resistance (APR) for durable resistance.
Conclusion. Molecular tools such as GWAS, marker-assisted selection, and genomic selection offer strong potential to accelerate barley breeding for disease resistance. Future research should focus on gene pyramiding, use of diverse germplasm, and advanced approaches such as pangenomics and genome editing. These strategies will develop multi-disease resistant barley cultivars adapted to Kazakhstan conditions.