Abstract:
Salinity is one of the worst abiotic stresses that restricts the cultivable paddy-land areas in the
tropics. Sri Lanka inherits a traditional rice gene pool that contains the most important traits.
This study was carried out to screen 25 traditional rice accessions for salinity tolerance at the
seedling stage in Yoshida solution. Dormancy broken, surface-sterilized seeds were germinated
in distilled water for 3 days and germinated seeds were transferred to Yoshida solution with EC
3 dS/L for 3 days. After 3 days, seedlings were transferred to Yoshida solution with EC 6 dS/L
and seedlings were kept in the same solution for 16 days. On the 10th day and 16th day at salinity
treatment, plants were evaluated according to the visual scoring system adapted by IRRI. The
control experiment was carried out in the Yoshida solution. Two Pokkali accessions were used
as positive controls. At the end of the experiment, shoot and root dry matter reduction rates
compared to that of control plants were recorded. Data were analyzed using SPSS. Among the
tested 25 traditional rice accessions Kaluwee (3728), Pokkali (3573, 3567), Rathuwee (3905),
and Rathu heenati (4992) were highly tolerant while Heenati (3998), Kaluheenati (4621),
Murungakayan (3489), Polayal (93661), Ratawee (3466, 3473), and Suduhenati (7799) were
tolerant at the 10th day of the stress treatment. By the 16th day of the salinity stress, Rathu
heenati (4992) accession was highly tolerant, and Kalu wee (3728), and Pokkali (3573, 3567)
accessions were tolerant. Two principle components (PC) were extracted in factor analysis that
explained 51% and 32% variance, respectively. According to the hierarchal cluster analysis, four
different clusters were identified at the cluster distance 5. Fifty-four per cent of the visual score,
85.4% of root dry matter reduction rate and 70.8% of shoot dry matter reduction rate
contributed for PC1. The present findings are very much important for utilizing traditional rice
accessions for future rice improvement programs for salinity tolerance.
