RESUMEN
Barley (Hordeum vulgare L.) thrives in the arid and semi-arid regions of the world; nevertheless, it suffers large grain yield losses due to drought stress. A panel of 426 lines of barley was evaluated in Egypt under deficit (DI) and full irrigation (FI) during the 2019 and 2020 growing seasons. Observations were recorded on the number of days to flowering (NDF), total chlorophyll content (CH), canopy temperature (CAN), grain filling duration (GFD), plant height (PH), and grain yield (Yield) under DI and FI. The lines were genotyped using the 9K Infinium iSelect single nucleotide polymorphisms (SNP) genotyping platform, which resulted in 6913 high-quality SNPs. In conjunction with the SNP markers, the phenotypic data were subjected to a genome-wide association scan (GWAS) using Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK). The GWAS results indicated that 36 SNPs were significantly associated with the studied traits under DI and FI. Furthermore, eight markers were significant and common across DI and FI water regimes, while 14 markers were uniquely associated with the studied traits under DI. Under DI and FI, three (11_10326, 11_20042, and 11_20170) and five (11_20099, 11_10326, 11_20840, 12_30298, and 11_20605) markers, respectively, had pleiotropic effect on at least two traits. Among the significant markers, 24 were annotated to known barley genes. Most of these genes were involved in plant responses to environmental stimuli such as drought. Overall, nine of the significant markers were previously reported, and 27 markers might be considered novel. Several markers identified in this study could enable the prediction of barley accessions with optimal agronomic performance under DI and FI.
RESUMEN
<b>Background and Objective:</b> Barley is considering one of the most important cereal crops at the local and global levels. It is ranked second in terms of nutritional importance after wheat and its flour contributes significantly to bridging the large nutritional gap in the production of Egyptian bread. The aim of this study concentrated on knowing and testing the genetic behaviour responsible for salinity stress tolerance in barley as trying to improve barley crop and increase its ability for abiotic stress resistance under Egyptian conditions. <b>Materials and Methods:</b> Twenty-one crosses and ten parents of barley with different responses to salinity tolerance were evaluated in this investigation under normal and salinity conditions. Yield and its components and some physiological traits related to salt stress tolerance were the most important studied attributes evaluated in this regard under both conditions. Moreover, SSR markers were used to evaluate and identified associated markers for salinity tolerance in selected hybrids and comparing among the ten barley parents. <b>Results:</b> The final results confirmed that the three testers; Giza 123, Giza 126 and Giza 2000 besides; the crosses; Line 1XTester 1 (Giza 125XGiza 123), Line 2XTester 1 (Giza 133XGiza 123), Line 1XTester 2 (Giza 125XGiza 126), Line 2XTester 2 (Giza 133XGiza 126) and Line 1XTester 3 (Giza 125XGiza 2000) exhibited highly salinity tolerance under saline stress treatment compared with the control experiment. Among 15 analyzed barley entries, the chosen set of 11 markers amplified 20 alleles with an average of 1.81, with a range from 1-4 alleles. <b>Conclusion:</b> The results of SSR analysis and the data on valued agricultural trait loci determined the genetic distance among parents and their hybrids, which is of an unlimited rate for breeders.