Genome-wide association analysis of chickpea germplasms differing for salinity tolerance based on DArTseq markers.

Soil salinity is significant abiotic stress that severely limits global crop production. Chickpea (Cicer arietinum L.) is an important grain legume that plays a substantial role in nutritional food security, especially in the developing world. This study used a chickpea population collected from the International Center for Agricultural Research in the Dry Area (ICARDA) genebank using the focused identification of germplasm strategy. The germplasm included 186 genotypes with broad Asian and African origins and genotyped with 1856 DArTseq markers. We conducted phenotyping for salinity in the field (Arish, Sinai, Egypt) and greenhouse hydroponic experiments at 100 mM NaCl concentration. Based on the performance in both hydroponic and field experiments, we identified seven genotypes from Azerbaijan and Pakistan (IGs: 70782, 70430, 70764, 117703, 6057, 8447, and 70249) as potential sources for high salinity tolerance. Multi-trait genome-wide association analysis (mtGWAS) detected one locus on chromosome Ca4 at 10618070 bp associated with salinity tolerance under hydroponic and field conditions. In addition, we located another locus specific to the hydroponic system on chromosome Ca2 at 30537619 bp. Gene annotation analysis revealed the location of rs5825813 within the Embryogenesis-associated protein (EMB8-like), while the location of rs5825939 is within the Ribosomal Protein Large P0 (RPLP0). Utilizing such markers in practical breeding programs can effectively improve the adaptability of current chickpea cultivars in saline soil. Moreover, researchers can use our markers to facilitate the incorporation of new genes into commercial cultivars.

Wheat Resistance to Stripe and Leaf Rusts Conferred by Introgression of Slow Rusting Resistance Genes.

Twenty-three wheat genotypes were evaluated for stripe and leaf rusts, caused by Puccinia striiformis f. sp. tritici and Puccinia triticina f. sp. tritici, respectively, at seedling and adult stages under greenhouses and field conditions during the 2019/2020 and 2020/2021 growing seasons. The race analysis revealed that 250E254 and TTTST races for stripe and leaf rusts, respectively were the most aggressive. Eight wheat genotypes (Misr-3, Misr-4, Giza-171, Gemmeiza-12, Lr34/Yr18, Lr37/Yr17, Lr46/Yr29, and Lr67/Yr46) were resistant to stripe and leaf rusts at seedling and adult stages. This result was confirmed by identifying the resistance genes: Lr34/Yr18, Lr37/Yr17, Lr46/Yr29, and Lr67/Yr46 in these genotypes showing their role in the resistance. Sids-14 and Shandweel-1 genotypes were susceptible to stripe and leaf rusts. Twelve crosses between the two new susceptible wheat genotypes and the three slow rusting genes (Lr34/Yr18, Lr37/Yr17, and Lr67/Yr46) were conducted. The frequency distribution of disease severity (%) in F2 plants of the twelve crosses was ranged from 0 to 80%. Resistant F2 plants were selected and the resistance genes were detected. This study is important for introducing new active resistance genes into the breeding programs and preserving diversity among recently released wheat genotypes.