Genetic Structure of Salinity Tolerance in Rice at Seedling Stage

Abstract

The<em> Oryza sativa</em> 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 dSm^-1) for 7 d, then NaCl concentration was increased to 163.8 mM (12 dSm^-1) 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, qCHLN-8, qSLN-8, qWLN-3, qWLN-9, qLAN-3, qLAN-8 and qLAN-9, qRFWN-1, qRFWN-3b and qRFWN-8, qFBN-7, qRDN-1a and qRDN-3 and qNaKSHN-5 under normal conditions and qSL-8, qLL-1a, qNaR-3, qKSH-1 and qKSH-4 and qNaKSH-4 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.