Rice (Oryza sativa L.) is one of the most essential food of people around the world, especially ‘KDML105’ which is widely known for its great mouthfeel and aroma. Drought stress has long been a major problem affecting rice productivity. However, drought-tolerant cultivars has been developed to overcome this problem. In this study, four chromosome substitution lines (CSSLs) from back-crossing of ‘KDML105’ and DH212 were used to evaluation of proper drought responsive traits in rice seedlings. The experiment was carried out with three water levels consist of 100%, 75%, and 50% field capacity. Results showed that chlorophyll fluorescence (Fv/Fm ratio) and stay green score were suitable parameters for the selection of drought-tolerant lines. Moreover, this study also showed that the difference in drought tolerance capability was due to genetic variation.

Thesis (M.Sc.)--Chulalongkorn University, 2014