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.
