Changes in Grain Quality, Amylose and Protein Contents Under High Temperature During Grain Filling Stage Among Korean Rice Cultivars

다국어 초록 (Multilingual Abstract)

A total of 40 Korean rice cultivars were exposed to high temperature during grain filling stage in the greenhouse condition and changes in head rice ratio of brown rice, whiteness of milled rice, amylose and protein contents were investigated in comparison with field-grown plants. Testing cultivars were categorized into four groups according to maturation period and accumulated temperature was 1216.4～1775.8oC in the field condition and 1275.8～ 1893.7oC in the greenhouse condition during grain filling stage. Reduction ratio of head rice and whiteness under high temperature in the four groups were 23.6, 17.7, 13.0, 8.7% and 12.7, 12.3, 9.5, 6.0%, respectively, in which early-maturing group showed more severe deterioration due to the early exposure to high temperature. Rice cultivar Dongan and Daeya were the most tolerant to high temperature among the tested cultivars showing 0.5 and 6.6% of the head rice reduction ratio and 0 and 1.2% of whiteness reduction ratio under high temperature, respectively. Amylose contents of the four groups were reduced by 11.7, 11.3, 8.8, 8.5% under high temperature in group Ⅰ, Ⅱ, Ⅲ, Ⅳ, respectively, whereas protein contents were increased by 14.2, 6.3, 4.4, 4.4% in the four groups, respectively.