Salinity tolerance and traits correlations of selected Magic indica rice (Oryza sativa L.) genotypes at seedling stage
2018
Samaco, M.A. | Villa, N.O. | Gregorio, G.B.
Salinity tolerance of MAGIC (Multiparent Advanced Generation Intercross) indica population of rice (Oryza sativa L.) was investigated at the seedling stage through phenotypic screening, morpho-physiological measurements and SSR analysis. Out of the 970 MAGIC rice genotypes, 205 genotypes were initially selected based on salinity tolerance. After a second screening, 36 lines were subjected to a final replicated screening along with eight founder lines of MAGIC indica, and two checks (FL 478 and IR 29). Ten MAGIC indica genotypes (28%) were scored as tolerant and 26 (72%) moderately tolerant. Among the founder lines, IR 45427-2B-2-2B-1-1 scored tolerant, 4 lines scored moderately tolerant and 1 scored susceptible. Relatively, the percent reduction in fresh weight content for shoot biomass was observed to be higher among the genotypes than percent reduction in dry weight content. A reverse trend was observed for percent reduction in root biomass. Genotypes under normal treatment were observed to have longer roots and shoots than salt-stressed treatments. Comparatively, the Na+ -K+ ratios of selected lines under salt stress were higher than the tolerant check, FL 478 except for IR 95044:4-B-5. A total of 32 SSR markers were used revealing 93 alleles. Twenty markers exhibited locus heterozygosity while five markers were monomorphic. RM 3843 exhibited the highest PIC (0.6489) while RM 315 exhibited the lowest (0.0830). No consistent clustering relationship among the genotypes based on the results of the phenotypic evaluation and Na+ -K+ ratio values was observed except for IR 95044:4-B-4 which were closely grouped with the tolerant check FL 478 and the founder line, IR 45427-2B-2-2B-1-1 which exhibits seedling stage salinity tolerance.
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