Assessment of Some Promising Lines of Rice (Oryza sativa L.) for Salt Tolerance using Microsatellite Markers Associated with the saltol QTL

抄録

Rice is one of the most important staple food crops in the world that grown extensively under irrigation. Salinity is an important physical factor influencing rice (Oryza sativa L.) production. To assess this limiting factor, YAU developed 100 breeding lines of rice. After screening at seedling and vegetative stages at different salinity levels (0.2, 6.0, and 8.0 dS m^-1), seven rice lines were selected as moderately saline-tolerant genotypes. These seven lines (V1: YAU- 1211-14-1-1; V2: YAU1201-90-2-4; V3: YAU-1211-18-1-1; V4: YAU1211-195-1-1; V5: YAU-1201-26-1-1; V6: YAU1201-26-1-3; and V7: YAU-1211-82-1-1) along with three local control varieties (Yatanatoe, Superhnankaut and Theehtatyin), one salt tolerance check (Pokkali) and one susceptible check (IR 29) were used in this study. Seven Saltol QTL associated SSR markers (RM5, RM9, RM140, RM472, RM493, RM1287 and RM3412) were used to check the usefulness of microsatellite (SSR) markers associated with Saltol QTL. The number of alleles on the SSR markers ranged from 2 for RM140 to 4 for RM3412. Polymorphic information content (PIC) value varied from 0.00 for RM140 to 0.62 for RM3412, with an average of 0.36. The SSR marker, RM3412, was found to be superior for analysis as an indicator of genetic diversity in this study. Cluster analysis of the rice genotypes based on SSR data divided the genotypes into three groups, each of which include Yatanatoe, Theehtatyn, Superhnankaut and susceptible check IR29 (cluster 1), V1, V2 and V3 (cluster 2), V4, V5, V6, V7 including salt tolerance genotypes Pokkali (cluster 3), respectively. Of the seven lines, four SSR markers (RM5, RM493, RM1287 and RM3412) could discriminate Pokkali (saltol) from the IR29 (susceptible) genotype. Two specific alleles were found by RM5 (170) and RM493 (220) for Pokkali. At locus RM140, almost all genotypes possessed the same allele as Pokkali (260) except Theehtatyin and IR29 (null allele). RM1285 indicated four YAU rice lines (V4, V5, V6 and V7) as salt tolerance lines. The study revealed V4: YAU1211-195-1-1 as a tolerance genotype. The RM5, RM493, RM1287 and RM3412 markers were able to discriminate the tolerant genotypes and hence could be useful for marker-assisted selection of Saltol QTL.