Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Australie → 2021 → The genetics of barley (Hordeum vulgare) salinity tolerance during germination and the instantaneous seedling endurance

Murdoch University (2021)

The genetics of barley (Hordeum vulgare) salinity tolerance during germination and the instantaneous seedling endurance

Mwando, Edward Kulecho

Titre : The genetics of barley (Hordeum vulgare) salinity tolerance during germination and the instantaneous seedling endurance

Auteur : Mwando, Edward Kulecho

Université de soutenance : Murdoch University

Grade : Doctor of Philosophy (PhD) 2021

Résumé partiel
Salinity limits crop production through osmotic and ionic stress in combination with oxidative strain and nutrient imbalance. Osmotic tolerance, ionic exclusion, and tissue tolerance are some of the adaptive mechanisms in plants when exposed to salinity stress. These physiological adaptive mechanisms are quantitative in nature and are manifested genetically by affecting 8% of genes expression. Barley, the fourth most important cereal crop in the world, is relatively salinity tolerant. However, salinity causes a significant reduction in its growth and grain yield. Adaptation to salinity in barley is varied with growth stage where germination and early growth stages are the most sensitive. This is because excessive salt accumulation in the rhizosphere affects the germinating seed and the subsequent developmental processes including revitalization of plants development after exposure to salinity stress during the sprouting stage. Studies are yet to close the lack of information between the germination and/or seedling stage salinity tolerance, and the genotypic differences in developing young plants regeneration after exposure to salinity stress. The current study explored the genetics of salinity tolerance during the germination stage and the seedling survival in barley after germination under salinity stress (NaCl). To detect the genetic loci and candidate genes responsible for salinity tolerance in barley during germination and early growth stages, four barley populations comprising of a diversity panel of 350 accessions from across the globe, two doubled haploid (DH) populations (CM72/Gairdner and Skiff/CM72), and a back-cross population of CM72/Gairdner/*Spartacus CL were used for phenotyping and mapping. These germplasm sets were exposed to different levels of salinity stress (75, 90, 120 AND 150 mM NaCl) along with a control treatment (deionized water) and various phenotypic traits recorded at germination and early seedling stages. Genome-Wide Association (GWAS) analysis was conducted on a diversity panel of 350 accessions using 24,000 genetic markers, where 19 Quantitative Traits Nucleotides (QTNs) were detected across all 7 barley chromosomes and 4 genes predicted for salinity tolerance at germination. A study with CM72/Gairdner DH population mapped six Quantitative Traits Loci (QTLs) on chromosomes 1H, 3H and 4H for traits associated with seedling survival under salinity stress

Présentation

Version intégrale (7 Mb)

Page publiée le 3 novembre 2021