Drought-tolerant characters, yield and its component of an elite landrace upland rice cultivars in Thailand

Abstract

In Thailand, rice are cultivated on the rainfed unbunded upland environment about 0.928 million ha annually, which usually subject to drought stress due to an eratic rainfall throughout growing season, and usually having low yield stability and productivity. Two experiments were characterized a drought tolerant-related physiological traits, yield and its components of 6 elite landrace upland rice cultivars (Niaw Dum Luem Phua, Dawk Pa Yawm, hukaothong 2, Sew Gliang, Sam Deuan, and  Leb Nok) with IR1552, and Khao Dawk Mali 105, a moderate drought-tolerant check varieties. The first experiment was carried out at King Mongkut’s Institute of Technology Ladkrabang, Bangkok during Aug-Sep 2018 for 4 drought tolerant-related characters at maximum tillering including longest root, root dry weight, root/shoot dry weight ratio, and stomatal conductance. The germinated seeds were grown in a cylindrical like-shape plastic pots, data were recorded for 10 hill/experimental unit. The second experiment was conducted at the experimental field of Rajamangala University of Technology Tawan-Ok, Chon Buri province, on loammy-sand, unbunded upland field under natural rainfed in rainy season (Jul-Nov), 2018. Ungerminated seeds were directly planted with space of 25x25 cm, yield and yield components were sampling recorded for 10 hill/experimental unit. All studied characters among cultivars; longest root, root/shoot dry weight ratio, stomatal conductance, yield and all yield components except, root dry weight were highly significant different (p≤0.01). IR1552 had the highest yield of 72.52 g/hill. Among 6 landrace cultivars, Niaw dum luem phua showed the highest drought tolerant-related characters, yield components, and rough yield of 59.77g/hill. While, Khao Dawk Mali 105 had rough yield of 51.42 g/hill.