Mapping quantitative trait loci (QTLS) for salt tolerance in rice(Oryza sativa) using RFLPS

Recombinant inbred (RI) lines derived from a cross between Tesanai2 (moderately salt tolerant) and CB (salt sensitive) through single seeddescent procedure were used to identify RFLP markers linked to QTLsinvolved in salinity tolerance. The R1 population (F8) was evaluated forsix different parameters using Yoshida's modified nutrient solution at anEC level of 12 dSm- 1. The genotyping of 96 RI lines utilized 74 RFLPmarkers that revealed polymorphism. A linkage map was constructed from12 linkage groups based on R1 segregation data. The map covered 1349.5cm of the rice genome with an average distance of 18.24 cm betweenmarker loci. Based on regression ANOVA (P = 0.05), one marker locus wasfound significantly associated with seedling survival days, 14 with dryshoot weight, 8 with dry root weight, 2 with shoot Na+ and 3 each withK+ and Na+/K+ ratio. The proportion of phenotypic variation explained byeach QTLs ranged from 4% to 15%. Common QTLs were observed fordifferent traits. The result explains much of the transgressive variationfor the most characters measured.