Growth, yield, yield components and drought tolerant traits to early season drought conditions of local rice varieties

Abstract

The objective of this study were to 1) investigate growth, yield and yield components of indigenous rice accessions under well-watered conditions and early season drought conditions, 2) to evaluate local rice varieties for early drought tolerance and 3) estimate correlations between grain yield with traits related to drought tolerance of local rice varieties. A split plot design with completely randomized arrangement of the treatments with four replications was used. Well-watered treatment and early season drought treatment were assigned in main plots and 25 accessions of indigenous rice were arranged in sub plots. Data were recorded for plant height, number of tillers, number of panicles, number of filled grains, number of un-filled grains, 1,000-grain weight, grain weight, dry straw weight, harvest index, leaf rolling, leaf senescence, ability to recover after re-watering and drought tolerance index. Indigenous rice accessions were significantly different for growth, yield, yield components, plant height, number of tillers, number of panicles, number of grains, 1,000-grain weight, grain weight, dry root weight and harvest index under well-watered condition and early season drought condition. Wid Nee, Hin Kong, Lueng Boon Ma, E-Noi and Kaw Dore had the highest grain weight in respective orders under well-watered condition. These accessions had not different grain yield from KDML 105 and RD6 under well-watered condition, whereas Kaw Dore, Nang Hok, Wid Nee and E-Noi had the highest grain dry weight in respective orders under early season drought condition, but they also has no different grain yield than did KDML 105 and RD 6. The indigenous rice accessions were not different for drought resistance under early season drought condition as indicated by the differences in leaf rolling, leaf senescence, ability to recover after the water supply and drought tolerance index (DTI) under drought condition. However, the high-yielding rice varieties
under early season drought condition had DTI for grain weight and DTI for root dry weight.