Physiological and genetic characterization of wheat lines sharply differing in sodium accumulation

SILVA, MAURO; MORICONI, JORGE I.; GUALANO, LEONARDO; TRANQUILLI, GABRIELA E.; GUILLERMO E. SANTA MARÍA

rosario

Congreso; XXXIV Reunión de la Sociedad Argentina de Fisiología Vegetal; 2023

SAFV

A former Genome Wide Association study allowed us to identify T. aestivum genomic regions involved in setting high sodium (Na) accumulation at the seedling stage under conditions of low potassium (K) supply. In this work we firstly ranked the lines examined and selected three of high and three of low Na accumulation. We next evaluated the pattern of growth, Na and K accumulation in those lines when grown at either optimal or limiting levels of K supply and then attempted to advance towards the validation of candidate regions through a biparental population approach, using contrasting genotypes for Na to derive F2 families.We observed differences in Na accumulation among genotypes in the aerial plant fractions, which were considerably increased under limiting K supply. Interestingly, genotypic differences in Na accumulation, which were found to involve differences in Na uptake and translocation, were companied by genotypic differences in Potassium Utilization Efficiency (KUtE), thus suggesting the suitability of Na accumulation based approaches to improve KUtE. Interestingly, differences in KUtE were not necessarily associated to differences in tolerance to low K supply, thus indicating that, at least for the lines examined, the positive influence of Na does not equally impact on all the desired agronomic traits at the vegetative stage.Next, we used two sets of biparental lines. Non-destructive phenotyping of 87 and 89 F2 individuals, grown at low K supply, was companied by genotyping through two 1BL region-flanking SSR markers for each family, as far as the 1BL chromosome region may account for ~25% of the total variation in Na accumulation. A bimodal frequency distribution of both F2s was observed suggesting a dominant Mendelian distribution for the trait. All evaluated SSR showed a significant cosegregation with [Na] for both F2 families. These data confirm region 1BL as a strong candidate for the major differences found in Na accumulation at low K supply.