AUTHOR=Hiddar Houda , Rehman Sajid , Belkadi Bouchra , Filali-Maltouf Abdelkarim , Al-Jaboobi Muamar , Verma Ramesh Pal Singh , Gyawali Sanjaya , Kehel Zakaria , Amri Ahmed 

TITLE=Identification of sources of resistance to scald (Rhynchosporium commune) and of related genomic regions using genome-wide association in a mapping panel of spring barley

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1133404

DOI=10.3389/fpls.2023.1133404

ISSN=1664-462X

ABSTRACT=Barley is an important crop worldwide known for its adaptation to harsh environments and used in multiple forms as feed, food and beverages. Its productivity is affected by major abiotic and biotic stresses. Scald caused by hemibiotrophic fungus Rhynchosporium commune is a major foliar disease in many parts of the world. Host plant resistance is targeted by breeders to efficiently control this disease. An association mapping panel of 316 spring barley genotypes (AM17) was screened for seedling resistance under greenhouses against three isolates and for adult plant resistance in three fields in Morocco. The phenotyping results showed different numbers of entries with resistant and moderately resistant reactions at both seedling and adult plant stages. The reactions differed between the isolates with the highest percentage of resistant genotypes observed for isolate SC-S611 (49.4%) and highest percentage of susceptible genotypes (73.8%) for isolate SC-1122. At adult plant stage, the highest percentage of scald resistant genotypes (64.5%) was observed at Rommani region compared to 56% at Guich site and only 28.8% at Marchouch site. Seven genotypes were resistant at the seedling and adult plant stages. Genome wide association study (GWAS) revealed 219102 MTA (3115 QTL) at the seedling stage, and 11925 MTA (4412 QTL) associated with scald resistance at the adult plant stage. In addition, the sequences of 20092 out of 219102 at SRT, and 11424 out of 11925 significant SNP markers at APR were located in genomic regions enriched with functional proteins involved in diverse cellular processes including disease resistance. These markers span over all chromosomes with the majority of SNPs located on 3H and 7H. This study has verified 3418 QTL reported in previous studies. In addition, it was successful in identifying new sources of resistance and novel genomic regions which could help in enhancing scald resistance in barley breeding programs.