Correlation studies for growth and physiological parameters in upland and lowland rice varieties

Abstract

Salinity is one of the major stresses faced by crop plants in general and rice in particular. High levels of salinity inhibit growth, height and ultimately the yield. Salt tolerant rice varieties are essential for sustainable agriculture production and to address the food security issues. A total of five rice varieties (two upland; SK1, Panderas and three lowland; Pokkali, Firat, MR211) were tested under three salinity stresses [0mM, 80mM and 120mM] for growth and physiological parameters. The experimental treatments were compared using analysis of variance. The mean comparison of growth parameters were formulated using least significant differences. According to the IRRI standard evaluation system for salinity, Pokkali and Firat were given a score of 3 while MR211 and Panderas were given a score of 7. Hence Pokkali and Firat were found to be salt tolerant while MR211 and Panderas were salt susceptible. One upland rice variety SK1 was found to be moderately tolerant to salinity stress. A highly significant negative correlation was found between sodium ion contents and all the growth parameters for all the varieties. Reduction in potassium was also observed for all the varieties with increasing sodium ion contents. These findings reflect that sodium contents and salt injury score would be screening index for salinity tolerance in rice. Furthermore, the availability of potassium might play its role in minimizing the deleterious effects of salinity stress.