The performance of single chromosome substitution lines of bread wheat subjected to salinity stress

The parents (the landrace Chinese spring (CS) and a synthetic hexaploids (S6x)) and 17 derived single chromosome substitution lines (SL) were grown in parallel in the field under non-saline (1.0 dSm−1) and saline (12.0 dSm−1) conditions, and evaluated for a set of phenotypic traits. The performance of CS indicated it to have borderline salinity tolerance with respect to all of the traits except for leaf area (for which it behaved in as a salinity sensitive type). The SL 4D was early in booting, ear emergence, flowering and maturity, while 5D and 2B SLs were both late. The 2B SL produce 33% more ears than CS. The 5D SL under-performed with respect to ear weight, grain number per ear, grain weight per ear and 1000-grain weight both under non-saline and saline conditions. Under saline conditions, four SLs (1A>5A>1D>2B) outperformed Cs for ear length, and six SLs (1D>6A>4B>3A>3B>3D) showed an improved grain weight. The grains produce by the 2B SL were smaller than those of CS. Leaf area developed better in four SLs (4D>2B>1A>7D) than in CS

Phenotypic and genotypic characterization of salt-tolerant wheat genotypes

To determine limits of tolerance, provide information about genetic diversity, and explore potential as progenitors for a salt-tolerant wheat improvement program, we collected several landraces and genotypes reputed to be salt-tolerant. Salt tolerance was tested by irrigation with a diluted solution of seawater with 12 dS.m −1 electrical conductivity for two years. Phenotypic parameters of percent of emergence, days to flowering to spike emergence, and physiological maturity were not significantly affected. Leaf area was sensitive to salt stress and inhibited about 30%. Plant height was inhibited 30%, while spike length and number of grains per spike were not. Total yield of Shorawaki and Kharchia landraces confirmed their reputation as salt-tolerant. Cultivars Mepuchi, Pericu, Calafia, WH157, and SNH-1 were inhibited at a moderate level of tolerance; cultivars Cochimí, Lu26S, and KRL 1–4 were inhibited, as was the control cultivar Oasis by up to 50%. To amplify microsatellites from genomes A, B, and D, 33 pairs of primers were used. The microsatellite WMS169-6A was highly polymorphic, with 10 different alleles distinguishing the genotype set. Also, the short arm of chromosome 4D microsatellites were amplified and found to be monomorphic, which suggests highly conserved alleles. The other microsatellites had variable polymorphism. In total, 120 alleles were obtained and used to define genetic diversity. The resulting dendrogram showed that landraces Shorawaki and Kharchia are distantly grouped from all other cultivars, as well as the cultivar Chinese Spring. Strikingly, KRL1–4, a derivative of Kharchia, did not show a close relationship to its source. The geographic origin did not influence pair-wise combinations. However, pedigree did influence pair-wise combinations