MAPPING QUANTITATIVE TRAIT LOCI (QTLS) FOR SALT TOLERANCE IN RICE (ORYZA SATIVA) USING RFLPS

Abstract

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