Abstract
Salinity affects all growth stages of rice in varying degrees starting from germination up to maturation. The present study was conducted to screen the commonly cultivated rice varieties in salinity affected areas in Sri Lanka against salt stress. Screening of 21 improved rice varieties and check variety Pokkali was performed at seed germination, seedling and maturity stages in petri dishes, in a hydroponic system and in soil filled pots, respectively. Rice varieties were tested for ability to sustain seed viability, growth performance of seedling and plant survival, growth performance and grain yield reduction at maturity under salt stress. At germination stage, Bg 406 and Pokkali were identified as highly tolerant rice varieties whereas, At 402 showed the highest tolerance level followed by Pokkali, Bg 369 and At 354 at seedling stage. Based on the mean separation on survival of plants per pot at 12 dS/m and 8 dS/m, three groups (highly tolerant, tolerant and susceptible) could be identified. Percentage reduction increased with increasing salt levels for most of the parameters tested (PH, PL, RDW, SDW, PWT, PNO and YLD). Based on the phenotypic observations Pokkali was identified as high salinity tolerant variety whereas Bg 369, At 354, At 402 were identified as salinity tolerant varieties at maturity stage.
Highlights
Rice (Oryza sativa L.) is one of the most important cereal crops and serves as the staple food for nearly half of the world’s population (Mohammadi et al, 2010)
Response to salt stress at seed germination stage Two way interaction effects of variety × soaking period, variety × salt concentration and soaking period × salt concentration were found to be significant at 0.05 probability levels
The results showed that the height of rice at different levels of salinity (3.6 to 8.3 dSm-1) decreased but not statistically significant (Gridhar, 1988)
Summary
Rice (Oryza sativa L.) is one of the most important cereal crops and serves as the staple food for nearly half of the world’s population (Mohammadi et al, 2010). 21.5 million hectares of arable land in Asia are facing salinity problem and the estimated crop loss is up to 50% of fertile land by the 21st midcentury (Nazar et al, 2011; Huyen et al, 2013). Despite these challenges rice production has to be increased by at least 25% by 2030 to keep pace with predicted population growth (Li et al, 2014). It is comparatively tolerant to salinity during germination, active tillering and at maturity
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