稻米品质形成的气候生态条件评价及我国地域分布规律

The Evaluation of Climatic-Ecology Condition for the Rice Quality Formation and Its Distribution Laws in China

在多品种、多试点的田间分期播种和人工气候箱控温、遮光处理等试验的基础上 ,通过对影响稻米品质诸气候生态因子的相对重要程度及稻米品质形成与水稻灌浆结实期前 30 d的日均温度、日均太阳辐射间的关系进行分析 ,首先建立了稻米品质的温度评价函数 ,然后用分段法构建了稻米品质的日均太阳辐射量订正函数 ,将上述两式结合 ,则可得某一地稻米品质气候生态条件的综合评价函数。利用该公式 ,在全国选若干代表点计算其稻米品质的评价指标值 ,并以此为基础 ,分双季早籼、双季晚籼、单季粳稻与双季早粳、双季晚粳 4大类型描绘出我国不同气候生态条件下稻米品质的地域分布框架图。

The effect of climatic factors on twelve quality traits of eleven rice varieties (japonica and indica) was studied in the field as well as growth chambers. The field trials comprising 10～14 sowing dates were conducted at thirteen locations representing six diverse climatic regions of China. Six shading treatments were imposed on plants at full heading stage. Shading treatments consisted of 10, 25, 40, 55, 68, 80 per cent shaded area of plants and control. In another study, rice plants were transferred from glasshouse where controlled temperature and light intensity were provided, to different climatic chambers at full heading stage until harvest. The rice quality parameters studied were brown rice rate, milled rice rate, heading milled rice rate, length, shape and transparency of grain, rate and degree of chalkiness, gelatinization temperature, amylose content, gel consistency and protein content. The climatic factors were found to have exerted significant influence on the quality of rice grain. The relative important degree of six climatic factors on rice quality was ranked by their effect coefficient. These studies reveal that the daily mean temperature was the most important climatic factor affecting rice quality followed by solar radiation intensity. The optimum temperature for the best quality rice ranged between 21.10℃ and 24.14℃ for 7 indica varieties and between 21.05℃ and 22.28℃ for 4 japonica varieties. The findings of shading effect have indicated that lesser the solar radiation (i.e. more the shading), poor was the rice grain quality. Based on the data from field and growth chambers, polynomial regression models of rice quality related to daily mean temperature and solar radiation intensity were constructed. These models can be used to determine the quality of rice at any particular location by fitting the daily mean temperature and daily mean light intensity data. These models suggest that the quality of single season japonica rice and two season early japonica rice produced in north China is superior to that produced in south China. Northeastern plain and northwest plateau basins are the best to produce superior quality of single season japonica and two season early japonica rice. Similarly, quality of late rice is superior to early rice. The climatic conditions during growing period of two season late indica and two season late japonica are generally more favorable for superior quality of rice than those available to two season early indica varieties. The quality of single season japonica and two season early japonica rice produced in south China is inferior to that produced in north China.