Characterization of some Indian native land race rice accessions for drought tolerance at seedling stage

Abstract

In rice, a major cereal, drought stress is one of the major constraints for production and yield stability in rainfed ecosystems. In an effort to identify promising rice accessions having tolerance against drought, one hundred and thirty four land races that represent different geographic regions of India and a few from Indonesia and Philippines were examined at the vegetative stage under both field and laboratory conditions. Thirty-day-old seedlings were subjected to moisture stress and the experimental field conditions include a ground water table at a depth of > 90 cm, low soil moisture content (10-12%) and high soil moisture tension (up to -50 kPa) at 30 cm soil depth during the stress period. With an SES (Standard Evaluation System) score of 0-3 in the 0-9 scale, seventy eight accessions were scored as tolerant with twelve having '0' score, eighteen with '1' and forty eight with the score '3'. Of the seventy eight genotypes, thirteen had recorded yield over 1.0 t ha-1 while the tolerant (CR 143-2-2) and susceptible controls (IR 20) recorded 2.70 t ha-1 and zero yield respectively. The tolerant genotypes were also evaluated further against poly ethylene glycol-6000 induced osmotic stress at both germination (-6 bar) and seedling stages (-8 bar and -10 bar). From the pooled data, six genotypes i.e. IRGC 12263, IRGC 636, IRGC 45699, IRGC 40275, IRGC 53989 and IRGC 51231 were identified as drought tolerant with good yield potential (0.7-1.95 tha-1) under stress conditions.