INHERITANCE AND IDENTIFICATION OF MOLECULAR MARKERS LINKED TO SALT TOLERANCE IN LOWLAND RICE VARIETY 'LLR012'

Salinity is one of the most serious factors limiting the productivity of rice worldwide, generally overcome by the effective use of genetically tolerant cultivars. Use of salt tolerant Thai indigenous rice varieties can solve the fail adoption of exotic varieties. A population of 156 F-2:3 derived from a cross between IR29, salt sensitive variety, and tolerant variety LLR012 was evaluated at the seedling stage under nutrient solution until the NaCl concentration reached 12 dSm(-1). Also, the experiment was evaluated under salted field conditions. The salt injury score, root and shoot dry weight, plant height, and tiller/plant seedlings were recorded. Transgressive segregation was determined in all traits due to the quantitative inheritance with the modification of minor or additive genes. Several SSR markers associated with salt tolerance-related traits were identified from both parents. RM313 on chromosome 12 presented the highest regression coefficient (R-2) in the salt injury score (22.97%), root dry weight (22.95%), and shoot dry weight (16.30%). RM413 on chromosome 1 was high in R-2 for root/shoot dry weight (8.36%), plant height (42.66%) and tiller/plant (18.88%). RM 520 on chromosome 3 was high in R-2 for the flowering date (17.34%). The SSR markers associated with the salt tolerance-related traits identified in this study may prove useful for marker-assisted selection, specifically for developing new rice cultivars in breeding programs for salinity tolerance.