Abstract:

【Objective】 It is beneficial for improving the health of chronic patients to eat high resistant starch (RS) content rice, but variety with high grain RS content is still very rare. Evaluations of rice germplasms for grain RS contents and its environmental stability were carried out in this study, and the results could provide a reference for the discovery of rice germplasm resources with high RS contents and its production. 【Method】 Grain RS contents in rice germplasms were detected by the Megazyme method, and used the PAST software to complete the frequency distribution of these contents. The environmental stability of rice RS contents were tested by planting at multiple locations within one year, and its variance analysis were performed with DPS software. Grain amylase contents were tested according to the national standard GB/T15683-2008. 【Result】 The initial evaluations on RS contents of 1206 rice germplasms demonstrated that for most these rice with RS content were very low, and about 87.6% of the rice were less than 2.5%, only about 0.2% were higher than 10%. There was a significant positive correlation between rice RS and amylose content, but high RS variety was not discovered in high amylose germplasms. However, three varieties with RS content higher than 10% were screened in low amylose content germplasms, and one of them was a good quality soft rice variety Diangu2, which has RS and amylose content of 10.12% and 12.3%, respectively. It carried out regional tests for eighteen varieties with different RS contents planting at three very differ environmental conditions. The result of environmental stability analysis indicated that the contents of thirteen varieties were affected by differences in planting area, of the others were affected. Totally, the contents were affected by genotype, planting environment and genotype-by-environment interactions. 【Conclusion】 In this research, most rice resources have low RS content, and also detected a significant positive correlation between rice grain RS and amylase content. Therefore, it is possible to develop rice variety with high RS starch and good taste, according the high RS varieties were identified in low amylose content germplasms. The RS content was mainly affected by genotype, so the varieties with high RS contents were high at different environments, and the lows’ were still low. Then, the varieties with high RS content can grow in its suitable areas to produce rice, and the contents could not be significantly affected.

Key words: rice (Oryza sativa L.), germplasm resource, resistant starch, amylose, environmental stability