Effects of storage period and cultivated season on grain quality characteristics of selected improved and traditional rice (<em>Oryza sativa</em> L.) varieties in Sri Lanka

Abstract

The production of quality rice is determined by many properties and these properties affect the consumer preferences and commercial value of rice. Therefore, this study was done to investigate the several physical, physicochemical, and milling properties of 12 selected improved and traditional rice (Oryza sativa L.) varieties grown experimentally in plots using randomized complete block design, in three seasons (2022 Yala, 2021/22 Maha, and 2021 Yala). These rice varieties were cultivated and harvested at the Rice Research and Development Institute, Bathalagoda, Sri Lanka. Statistical analysis was done using SAS software package version 9.3. Significant (p<0.05) differences between rice varieties in the relevant seasons and between seasons were observed for all test parameters. The brown rice and hull percentages varied from 75-79% and 20-24%, respectively while the head rice yield varied between 56-71% for raw rice in the 2021 Yala season. In the 2021/22 Maha season, the brown rice and hull percentage varied from 74–80% and 20–25% for selected varieties. Except for the variety suduheenati, At 311 and At 362, the head rice yield varied between 50-67% in the 2021/22 Maha season. The brown rice and hull percentages varied from 75-79% and 21-25%, respectively while the head rice yield varied between 55-74% for raw rice, except for the variety At 311 and Bg 374 in the 2022 Yala season. Majority of rice varieties harvested in all three seasons showed an intermediate gelatinization temperature (70–74 ºC). At 362 rice variety in all three seasons showed low gelatinization temperature of 55-69ºC. Except for At 311, many varieties had high amylose contents during the 2021/22 Maha and 2022 Yala seasons. In the 2021/22 Maha season, there were significant (p<0.05) differences in bulk density, grain elongation, and thousand-grain weight and there was no significant (p>0.05) difference between the 2021 and 2022 Yala seasons. The information obtained can be used to choose suitable rice varieties for commercial cultivation in Sri Lanka and to plan post-harvest practices.