EFFECT OF SALINITY ON RHIZOBIUM SPECIES, NODULATION AND GROWTH OF SOYBEAN (GLYCINE-MAX L.)

A pot experiment was conducted to observe the growth, nodulation and i on accumulation of salt tolerant and salt sensitive cultivars of soybe an (Glycine mar L.) when grown in symbiotic association with rhizobium in the absence of mineral nitrogen at different salinity levels (0.05 , 0.1 and 0.2% NaCl). The rhizobium strains pre-tested for salt tolera nce were found more tolerant than the host plants. Plants were inocula ted with a mixture of rhizobial strains at the time of sowing in steri lized sand. Salts showed a greater inhibitory effect on nodulation at 0.1% NaCl with decreased nodule number and weight than the plant growt h. Soybean cultivar ICAL-132 showed better growth and produced more no dules by keeping law sodium in the shoot as compared to sensitive cult ivar Loppa which failed to survive at 0.2% NaCl. Salinity decreased po tassium concentration in all cultivars tested, but this reduction was also less in ICAL-132. K:Na ratios showed similar trends. A highly pos itive correlation was observed between nodules and shoot dry weight.