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

Abstract

Background and purpose. Barley (Hordeum vulgare L.) is a key cereal crop in Kazakhstan, ranking second after wheat and playing a crucial role in livestock production and food security. However, its productivity is significantly constrained by major fungal diseases, including net blotch, barley scald, powdery mildew, and stem rust, which can cause yield losses ranging from 10% to 40%, and up to 100% under severe epidemics. The purpose of this review is to summarize current knowledge on the genetic basis of resistance to these diseases, with emphasis on resistance genes, quantitative trait loci (QTLs), and their application in breeding programs under Kazakhstan conditions.

Materials and methods. This review is based on the analysis of published 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 attention was given to studies performed under agroecological conditions of Kazakhstan to evaluate resistance to major fungal pathogens and identify associated genetic loci.

Results. Recent studies have identified numerous resistance loci associated with major barley diseases. In Kazakhstan, GWAS revealed 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 several known resistance genes. These findings highlight the presence of both globally recognized and region-specific resistance sources in local germplasm. The results also demonstrate the importance of combining major resistance genes with quantitative resistance loci, including adult plant resistance (APR), to enhance durability.

Conclusion. The integration of molecular approaches such as GWAS, marker-assisted selection, and genomic selection provides significant opportunities to accelerate breeding for disease resistance in barley. However, challenges including pathogen evolution, genotype × environment interactions, and limited implementation of genomic tools remain. Future efforts should focus on gene pyramiding, utilization of diverse germplasm, and adoption of advanced technologies such as pangenomics and genome editing to develop resilient, multi-disease resistant barley cultivars adapted to the continental climate of Kazakhstan.