中文摘要：

为了探讨优质稻谷品质在播期间变异特征，以大粒型品种八桂香，小粒型品种桂华占、油占8号、七桂占等4个优质籼型水稻品种为材料，以中粒型品种珍桂矮为对照，进行分期播种，以农业部最新行业标准的一级优质籼稻标准为参考样，利用灰色关联度模型，求得参试品种与参考样的关联度系数，依米质优劣将不同品种排序。结果表明：籼型稻谷粒型影响稻谷品质优劣。播期的适当推迟对提高稻谷品质有利。品质的优劣与品种密切相关，优质品种是获得优质稻谷的重要前提，但是优质稻谷也受栽培方式和气候影响。稻米品质优劣既受播期影响也受品种、稻谷粒型影响。

英文摘要：

To analyze the variable parameters of Indica rice quality traits,five different cultivars including Baguixiang （long grain）, Guihuazhan, Youzhan 8, Qiguizhan （short grain） and Zhanguiai （middie-little grain,CK） and five sowing dates were selected. Main quality characters were determined based on the newest occupation standard of the Ministry of Agriculture. The grain quality from different cuttivat and sowing date were evaluated and ranged using the grey correlation model. Properly late sowing date was advantageous to improve the Indica rice grain quality. The high grain quality was closely related to the genotype. The high grain qualities were usually obtained from quality variety, but it was also af- fected by the cultivation measures and the weather condition. In rice production, high grain quality should be obtained by high quality variety selection combining with proper agronomic measures. The high grain qualities was affected by sowing date, but it was also influenced by the genotype and the grain size.