Quantitative trait loci (QTL) mapping for physiological attributes in a SeriM۸۲/Babax population of bread wheat under salinity stress at seedling stage

Salinity stress is a major limitation in wheat production. The lack of economically viable methods for screening salinity tolerance in the field is an obstacle to breeders. A population of recombinant inbred lines (RILs) were developed by crossing SeriM۸۲ and Babax for identification of quantitative trait loci (QTLs) for physiological traits including chlorophyll a, chlorophyll b and carotenoid content under non-saline and saline conditions in seedling stage by tagging ۷۴ simple sequence repeat (SSR), ۲۴۹ amplified fragment length polymorphism (AFLP) and ۲۶۴ diversity array technology (DArT). Linkage map of RILs comprised of ۲۱ linkage group covering A, B and D genome for tagging and maped QTLs with major and minor effect. B genome contributed to the highest number of QTLs. Using composite interval mapping, nine QTLs were identified; five were related to normal condition and four to salinity stress. These QTLs were located on chromosomes ۱D, ۲B, ۴B, ۶B, ۶D, ۷A and ۷B explaining ۵.۹۸ to ۸.۶۴% of phenotypic variation. Three major QTLs QChl b-۶B.NO, QCar-۲B.NO and QCar-۱D.ST for chlorophyll b and carotenoid linked with markers aac/ctc-۳, agc/cta-۸ and barc۰۰۶۲ were putative and explained ۸.۶۴, ۷.۴۱ and ۷.۹۶ % of phenotypic variation, respectively. These identified genomic regions can be used in marker assisted breeding after validation in various genetic backgrounds and environments for salt tolerance in wheat.

Keywords:

Chlorophyll , Composite interval mapping , QTL , Salinity stress , Triticum aestivum