Marker-assisted identification of novel genetic lines for salinity tolerance and their categorization for utilization in development of hybrid rice (Oryza sativa L.)

Identification of new sources of salinity-tolerant genotypes is prerequisite for rice breeding programs in different saline ecosystems. In the present experiment, we characterized 177 landraces from the Western Ghats of Karnataka under natural saline field conditions for two years using morpho-physiological and grain quality parameters. Significant variation was present among landraces for seedling stage and reproductive stage salinity tolerance. The nutrient composition analysis of grain revealed an increase in average grain protein and carbohydrate content under saline conditions. Evaluation of twenty-two SSR markers associated with the Saltol region validated RM140, RM1287 and RM562 as best markers to classify landraces for saline tolerance. Polymorphism Information Content and genetic diversity indices showed that the markers RM10748 and RM10864 were highly useful for distinguishing landraces. Further, to benefit the exploitation of heterosis, eleven maintainers were identified among tolerant landraces and these genotypes could be further developed into male sterile lines for production of salinity-tolerant rice hybrids. Comparison with ‘Pokkali’ for morpho-physiological traits along with molecular confirmation showed that the landraces ‘Doddabaikalu,’ Kalaadikonda,’ Gajagunda’ and ‘Anekombina batha’ were superior donors carrying genomic regions for salinity tolerance.