New evidence of QTLs attributed to salinity tolerance in rice

An F2:3 population derived from the cross between Tarommahalli (indica) and Khazar (indica) was used to mapping salt tolerance in rice. The linkage map constructed by 74 simple sequence repeat (SSR) molecular markers covered a total of about 1231.50 cM rice genome. Plant stand, chlorophyll content, root and shoot length, fresh weight of root and shoot, dry weight of root and shoot, Na+ uptake, K+ uptake, Na+/K+ ratio related to uptake ions and green leaf area were mapped. Four QTLs for root length under salt stress were detected on chromosomes 1, 4, 7 and 9. Also, two QTLs (on chromosome 9) for dry weight root and three QTLs for ion exchanges (on chromosome 3 and 10) were identified. Tarommahalli alleles in these loci increased salt tolerance. Of these QTLs, the five major QTLs with the very large effect, qRL-7 for root length, qDWRO-9a and qDWRO-9b for dry weight root, qBI-1a and qBI- 1b for biomass explained 16.21, 27.43, 25.50, 22.24 and 26.83% of the total phenotypic variance, respectively. All these results reinforced the idea that, new QTLs of this study play an important role in the growth of rice at seedling in Iranian local population under salinity condition.