Genetic Structure of Salinity Tolerance in Rice at Seedling Stage

The Oryza sativa L. F8 population derived from a cross between salt tolerance cv. Ahlemi Tarom and salt sensitive cv. Neda was used in the study. Germinated seeds floated on water for 3 d, and after were transferred to float on Yoshida’s nutrient solution for 11 d. two weeks after sowing, the seedling was transferred to nutrient solution containing 51.19 mM NaCl (electrical conductivity 6 dSm1) for 7 d, then NaCl concentration was increased to 163.8 mM (12 dSm1) for further 7 d. After this period, the traits were measured. The linkage map was performed using F8 populations, 40 SSR markers, 16 ISSR markers (76 alleles), 2 IRAP markers (7 alleles) and iPBS marker (3 alleles). The map length was 1419 cM with an average distance of 13.07 cM between the 2 adjacent markers. The QTL analysis showed that a total of 73 QTLs were identified that controlled 20 traits under normal and stress conditions. Among the QTLs, qCHLN8, qSLN8, qWLN3, qWLN9, qLAN3, qLAN8 and qLAN9, qRFWN1, qRFWN3b and qRFWN8, qFBN7, qRDN1a and qRDN3 and qNaKSHN5 under normal conditions and qSL8, qLL1a, qNaR3, qKSH1 and qKSH4 and qNaKSH4 under salinity stress conditions were identified. There are more than 20% explanations for phenotypic changes in the traits. These QTLs, due to the high percentage of justification after validation, could be a good candidate for selection programs with the help of markers in the population of recombinant lines of rice.