Variations in morphological traits, agronomic traits and traits related to drought tolerance in indigenous Thai rice varieties

Abstract

Indigenous rice is worth conserving as it possesses many important traits such as good table quality for consumers, resistance to biotic and abiotic stresses and, especially, quality of starch. The objectives of this study were to evaluate indigenous rice accessions collected in Northeast Thailand and select the superior accessions for further improvement of indigenous rice. Forty indigenous rice accessions were evaluated in a pot experiment in a split-plot design with completely randomized arrangement of the treatments and four replications for two years in 2014 and 2015. Main plots were two water regimes, including well-irrigated treatment and early season drought treatment; the subplots included 40 indigenous rice accessions. Well-irrigated treatment was higher than early season drought condition in terms of plant height, number of tiller per plants, number of ears per plant, number of unfilled grains per ear, grain weight per plant, straw weight per plant and shoot dry weight per plant; drought treatment was higher than irrigated treatment in terms of the number of filled grains per plant, 1000-grain weight and root dry weight; whereas these two types of treatment showed no differences in terms of the number of tillers/plant at 30 days after emergence and harvest index. The superior genotypes for each trait and the genotypes with better drought tolerance index were identified.