Abstract: There have been a lot of reports on the relationship between RVA profile of rice starch and the cooking and eating quality properties in rice, and on the differences of RVA profile in different cultivars of rice, too. There are, however, few reports on the differences of RVA profile of a same cultivar, which is planted at different sites and on relationship between the RVA profile and the altitude of planting sites. Through field experiments with different sowing dates and different planting altitudes in two years in Panxi region, Sichuan Province, these aspects were studied and presented in this paper. Among the characteristic values of RVA profile of rice starch, the setback viscosity(SBV) was the most strongly inflrenced by environmental factors. The RVA profile varied with the planting sites(Table 2).The 3D graph of breakdown viscosity(BDV, z) with altitude(x) and latitude(y) of planting sites were establiahed where the regression equation was z=z₀+ax+by+cx²+dy²(Table 4,Fig.3). From this graph, a "golden planting area" (the most suitable planting area)with... ...

Key words: Rice, RVA profile, Environmental factor, Altitude