Screening for salt stress tolerance in different varieties of Oryza sativa L.

Abstract

Soil salinity is one of the most important environmental factors that causes osmotic stress and limits plant growth and productivity of Oryza sativa, commonly known as rice. To improve yield in saline soil, one possible solution is to plant salt tolerant rice varieties in these areas. As a contribution along this line, the present study screened for salt tolerance of seven new varieties of rice developed by the Philippine Rice Research Institute (PRRI) and International Rice Research Institute (IRRI). NSIC 2010 Rc226 (TUBIGAN 20), NSIC Rc222 (TUBIGAN 18), NSIC Rc218 SR (MABANGO 3), NSIC Rc216 (TUBIGAN 17), NSIC Rc212 (TUBIGAN 15), NSIC Rc160 (TUBIGAN 14), and NSIC Rc156 (TUBIGAN 12) were grown on a hydroponic system together with three controlled varieties, Pokkali (salt tolerant), IR 74 (moderately tolerant) and IR 29 (sensitive). The nutrient solution was salinized to 12 deciSiemens for 16 days while maintaining the pH level to 5.0. The salt stress tolerance level was evaluated through visual scoring and comparisons of shoot length, root length and dry weight. Results showed that Rc222, Rc216, Rc160 and Rc156 were salt sensitive like IR 29, while Rc218 and Rc226 were found to be moderately tolerant. Rc212 was seen to have a potential salt tolerant characteristic as its results were between those of Pokkali and IR 74. Further studies should be made on Rc212 in order to confirm this promising result.