Screening eighty traditional and improved rice genotypes in Sri Lanka for salinity tolerance at the seedling stage in Yoshida solution

A total of eighty different rice genotypes consisting of fifty-three traditional rice accessions and twenty-seven improved rice varieties were evaluated for salinity tolerance. To identify the tolerant genotypes and the relationship between tolerance level with plant height and dry matter accumulation, the seedlings were subjected to electrical conductivity (EC) similar to 12 dSm(-1) for ten and sixteen days separately at the seedling stage. The salinity tolerance of the seedlings was evaluated by standard evaluation scores (SES). Plant height, and total, shoot, and root-dry matter were evaluated in stressed and controlled plants. Rathuheenati4992 was highly tolerant at salinity stresses, and Heenati4618, Kaluwee3728, Mawee (5531, 3618), and Pokkali3573 were highly tolerant at the 10-day and tolerant at the 16-day salinity stress. Pokkali3881 was moderately tolerant at both stress conditions. Improved rice varieties At354 and Bg250 were highly tolerant at 10-day salinity stress and tolerant at 16-day salinity stress. Cultivation of highly susceptible improved rice varieties, Bg360, At306, At362, Ld368 At405, At402, Ld371, Bw272-6b, Ld365, and Bg352 must be avoided in salinized soils. There was no correlation between plant height and salinity tolerance (r = -0.381, alpha = 0.000), salinity tolerance and total dry matter (r = 0.325 alpha = 0.002), salinity tolerance and root dry matter (r = 0.294, alpha = 0.008), or salinity tolerance and shoot dry matter (r = 0.061, alpha = 0.594). Plant height or dry matter accumulation can be considered unreliable parameters for salinity tolerance screening since they differ with the genotype. The highly tolerant and tolerant genotypes must be further studied at different growth stages.