RFLP and SSLP mapping of salinity tolerance genes in chromosome 1 of rice (Oryza sativa L.) using recombinant inbred lines

TL;DR: In this paper, the authors used restriction fragment length polymorphism (RFLP) and simple sequence length polymorphisms (SSLP) markers to saturate the segment of chromosome 1 containing a major salt tolerance gene controlling the Na+/K+ ratio.

Abstract: The study used restriction fragment length polymorphism (RFLP) and simple sequence length polymorphism (SSLP) markers to saturate the segment of chromosome 1 containing a major salt tolerance gene controlling the Na+/K+ ratio. RFLP and SSLP analyses were conducted to construct linkage maps based on an F8 recombinant inbred line (RIL) mapping population. The RFLP and SSLP linkage maps constructed in this study were found to be in the same order as published maps, implying the reliability of the constructed maps. The integrated RFLP and SSLP linkage map had a total of 129.9 cM, with an average interval size of 6.8 cM. Two RFLP markers C52903S and C1733S, with 10.1 and 22.6 cM distance, respectively, flanked the major gene, Saltol. A published RFLP-saturated molecular map based on an F2 mapping population had a 5 cM interval between the two markers, C52903S and C1733S, which implies that the Saltol marker and the use of less than 80 RILs may be overestimating the distance between the two markers, and hence, the actual location of the salt tolerance gene. Two microsatellite markers, RM23 and RM140, flanked the Saltol gene with 16.4 and 10.1 cM distance, respectively. A common QTL for three quantitative traits (low Na+ absorption, high K+ adsorption, and a low Na+/K+ absorption ratio) was observed from position 50-65 cM segment of the map with peak LOD score 6.7. The Na+, K+ and the Na+/K+ absorption ratio QTLs accounted for 39.2, 43.2% of the phenotypic variation. RM140, a microsatellite marker, and C52903S, a RFLP marker, flanked the QTL peak within a 91.9 cM interval