Grain Amylose Content and its Stability over Seasons in a Selected Set of Rice Varieties Grown in Sri Lanka

Abstract

Grain amylose content, one of the key parameters determining cooking and eating quality of rice, varies among varieties. Identification of varieties with different grain amylose contents that are stable over seasons is important to improve the quality of rice. Present study evaluated 39 varieties of Sri Lanka for grain amylose content and its stability over seasons. Twenty six traditional and 12 improved rice varieties and 1 introduced rice variety were evaluated over 2006 Yala and 2006- 07 Maha seasons. Experiment in each season was conducted in a Randomized Complete Block Design at the Regional Rice Research and Development Center, Bombuwela. Amylose content was determined by standard iodine colorimetric method. Grain amylose content significantly varied from 23 to 31% among varieties. Irrespective of traditional or improved, all the varieties except Suduru Samba and Basmathi 370 (intermediate amylose contents: 20-24%), had high amylose contents (≥25%) in both seasons. In both traditional and improved varieties, varietal differences for stability of grain amylose content over seasons were found. Higher proportion of improved varieties showed stable amylose content over seasons than that of traditional varieties. Interestingly, both the varieties with intermediate amylose showed stability over seasons. Varieties with high and intermediate amylose contents that are stable over seasons are valuable germplasm in terms of grain amylose content. Therefore, such varieties can be used in rice grain quality improvement program in Sri Lanka.