Physiological Response to Salinity and Alkalinity of Rice Genotypes of Varying Salt Tolerance Grown in Field Lysimeters uri icon

abstract

  • Soil salinity and alkalinity seriously threaten rice production in south Asia. Improving screeningmethodologies to identify sources of tolerance for improved breeding for salt tolerant rice is ofcontinuing importance. Rice genotypes of varying salt tolerance, such as tolerant (T), semi-tolerant(ST), and sensitive (S), were grown in field lysimeters in saline soil of ECe 4 and 8 mS cm-1 and alkalisoil of pH 9.5 and 9.8 in North India and analyzed for chlorophyll (Chl), sugar, starch and proline inleaves. Chlorophyll a and b decreased due to salinity in all the tolerance groups. However, Chl awas not much affected but chl b increased with alkalinity. Under high stress both at ECe 8 and pH9.8 Chl a and b were more in tolerant than in sensitive genotypes. The ratio of Chl a/b was similarin T, ST and S genotypes under salinity stress. Sugar accumulation was higher in T compared to Sunder normal conditions but under salinity or alkalinity stress the differences were not significant.Leaf starch was highest in T, intermediate in ST and lowest in S genotypes in normal as well asunder salinity and alkalinity stress. There was decrease in starch with salinity and alkalinity stressonly in T group but not in ST and S group. Proline increased significantly in all the tolerance groupseven at low salinity of ECe 4 mS cm-1 or pH 9.5. The salt tolerant genotypes of rice maintainedhigher levels of Chl a and b, starch and proline under high salinity and alkalinity stress and are therobust criteria for tolerating high salinity and alkalinity

publication date

  • 2013