Growth, Yield and Mineral Composition of Three Rice Varieties Cultivated under Salt-Affected Conditions

A pot experiment was conducted to study the relative performance of IR 6,KS 282 and IR 10198-66-2 rice varieties cultivated under salt-affected conditions at EC of 6.0,9.0 12.0 dS m(-1) in a sandy clay loam soil havig ECe of 1.6 dS m(-1) treated as control. Six seedlings of 39-day old transplaned to each pot having 12 kg soil. The fertilizer as nitrophos and potassium sulphate at the rate of 57.0, 25.0 and 50.0 mg N,P and K kg(-1) soil respectively was applied at the time of transplanting while zinc sulphate at the rate of 5 mg Zn kg(-1) soil and 43.0 mg N kg(-1) of soil as additional dose were applied 19 and 30 days after transplanting respectively. Normal plant protection measures like number of tillers, panicles, paddy grains, filled and unifilled grains, yield per plant and sterility were recorded and shoot and straw samples were analysed for sodium, potassium, calcium and chloride contents. It was observed that growth and yield of all the varieties were reduced significantly with increasing soil salinity. Na/K and Na/Ca rations in shoot and straw increased significantly with increasing soil salinity. It was also observed that higher values of Na/K and Na/Ca rations in shoots affected growth parameters while higher values of these rations in straw affected yield components and grain yield. However, IR 6 having relatively lower values of Na/K and Na/Ca rations proved to be the most salt-tolerant rice among the three varieties studied.