Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 12/30/2003
Publication Date: 2/29/2004
Citation: Bryant, R.J., Gibbons, J. 2004. STARCH STRUCTURE AND PASTING CHARACTERISTICS OF RICE VARIETIES GROWN IN DIFFERENT LOCATIONS. Rice Technical Working Group Meeting Proceedings. Feb. 29 - March 3, 2004 pg. 138. Interpretive Summary:
Technical Abstract: Environmental conditions, such as temperature, affects rice grain quality. This change causes an increase or decrease in the market value. It is not known if some varieties are affected less than others. Therefore, the objective of this research was to examine rice varieties grown in different locations and analyze them for their starch structure and pasting characteristics. The algorithm used weather data from the nearest NOAA weather station to each site. The algorithm began calculating DD50 units beginning at the R3 growth stage (taken as 50% heading). From an archive of the DD50 interval between R3 and R8, the R6 growth stage period was predicted and the actual temperature during that growth stage was read. The 7 varieties, 1 medium grain japonica (Bengal), 2 long grain indicas (4484 and Zhe 733), and 4 long grain japonicas (Cocodrie, Cypress, Francis, and Wells), were grown in Arkansas (Ar), Cross (Cr), and Jackson (Ja) Counties, AR and Dunklin (Du) County, MO. Each variety was milled and analyzed for moisture, apparent amylose content, gelatinization temperature, viscosity profile and amylopectin chain length. The temperature during the R6 growth stage was also determined from a predictive program. Du had the lowest temperature, both high and low, during R6 growth stage, except for the low temperature of Cocodrie and Zhe 733 grown in Ar. The difference in apparent amylose content ranged from 0.8% for Francis to 2.4% for Bengal with the varieties grown in Cr having the lowest and Ja, Ar, and Du having the highest, respectively. RVA profile showed that setback 2, final viscosity minus the peak viscosity, for Cypress, Francis, 4484, and Wells grown in Du, which is the farthest north, were much greater than the others, which were closer to each other. Setback 1, final viscosity minus the trough viscosity, for all varieties other than Cocodrie were highest for the ones grown in Du. Setback 2 for Cocodrie, Zhe 733, and Bengal for the different locations were closer. Except for Cypress, setback 2 of the varieties grown in Ar, which is the farthest south, were lower than those grown in the other locations. Varieties grown in Du, which had the lowest average temperature during R6, had the lowest gelatinization temperature with Cr producing the highest, except for Cypress and Zhe733 grown in Ja. Starch profile and the amylopectin chain length differed over locations and the correlation between the starch profile, amylopectin chain length ratios, temperature, and amylose content is still being examined. This research shows that environment affects rice varieties differently and some varieties are more stable than others. This data can be of use to rice breeders in selecting future varieties.