EFFECT OF SALINITY ON GROWTH, YIELD AND YIELD COMPONENTS IN BASMATI RICE GERMPLASM

Salt tolerance of 4 commercial varieties and 17 breeding lines of Basmati rice (Oryza sativa L.) was assessed at early growth stage and at maturity in field plots artificially salinzed with NaCl and CaCl2 (1:1 by weight). The average electrical conductivity (EC) of soil was 1.2, 5.2 and 10.5 dS m(-1). Forty-five days after sowing (20 days in saline or control conditions), shoot dry weights and sodium (Na) and potassium (K) contents of shoot were determined. At maturity, plant height, number of tillers per plant, panicle length, number of grains per panicle, 1000-grain weight, grain sterility, shoot dry weight, grain straw ratio and grain yield per plant were measured. There was significant variation between genotypes for all the characters studied. On an average, plant height, number of tillers per plant, panicle length, number of grains per panicle, shoot dry weight, grain straw ratio, grain yield per plant, K content of shoot and K/Na ratio were reduced linearly while grain sterility and Na content of shoot were increased with increasing soil salinity. With increased salinity, reduced number of grains per panicle was mainly found responsible for reduction in grain yield. Generally genotypes having ability to exclude Na from shoot were found salt tolerant in respect of grain yield and vice versa. Na contents of shoot and shoot dry weight 45 days after sowing (DAS) showed significant correlations with grain yield. It is suggested that selection for salinity tolerance in rice can be carried out at an early stage of growth.