攀西地区稻米淀粉RVA谱的影响因子及其垂直变化特点

The Factors Influencing RVA Profile of Rice Starch and Their Changes with Altitudes in Panxi Region

通过2年在攀西地区不同海拔的分期播种试验研究表明,在稻米淀粉RVA谱各特征参数中以消减值(SBV)受环境条件的影响最大。栽培地点不同,稻米淀粉的RVA谱有较大差异,最高黏度(PKV)、崩解值(BDV)与种植地的海拔高度和纬度之间,呈三维凸型曲面关系,随着种植地海拔的升高,PKV和BDV先升后降,因此存在高值区域,即“最优种植区域”。不同品种的“最优区”不尽相同,粳型品种“最优区”的海拔高度较籼型品种高。PKV与播种期之间呈二次函数关系,但BDV随播种期的推迟而降低,SBV则随播种期的推迟而升高,因此应适时播种。在气候因子中,PKV、BDV与齐穗后20d的平均温度、最高温度、最低温度和日照时数正相关,而SBV则相反,不同品种的RVA谱对温度的敏感性不同。

There have been a lot of reports on the relationship between RVA profile of starch and cooking and eating quality properties in rice, as well as the differences of RVA profile in different rice cultivars . 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 influenced 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 established where the regression equation was z = z0 ＋ ax ＋ by ＋ cx^2 ＋ dy^2（Table 4, Fig.3）. From this graph, a ＂golden planting area＂ （the most suitable planting area）with highest BDV was found. The ＂golden planting area＂ varied with cultivars. The altitude of “golden planting area” of Japonica cultivars was higher than that of Indica cultivars. The relationship between peak viscosity（PKV） and sowing date fit a quadratic function, while the relationships of BDV and SBV with sowing date were linear function（Fig. 1）, so suitable sowing date is important. PKV and BDV were positively correlated with daily average temperature （ Fig. 2）, the highest temperature, the lowest temperature and daily sunshine hours in 20 days after full heading, while SBV was negatively correlated with those factors. Linear functions for hot viscosity（HTV） and final viscosity（FNV） with temperatures in 20 days after full heading varied with cultivars of rice（Table 3）. The sensitivity of these characteristic values of RVA profile to temperatures at grain filling stage also varied with cultivars of rice.