Changes of Grain Quality During Evolution of Mid-season Indica Rice Cultivars in Jiangsu Province

Mid-season rice (Oryza sativar L. subsp. indica) is the dominant type of cultivated rice in the Middle and Lower Yangtze River Region of China. This study aimed at studying the characteristics of evolution on grain quality in the mid-season rice cultivars commercially grown in Jiangsu Province, China since the 1950s. Thirteen cultivars or hybrids were selected to represent the types of early-tall, dwarf, semidwarf, semidwarf hybrid, and super rice according to their application times, plant types, and genotypes. The milling quality indicators, including brown rice rate, milled rice rate, and head milled rice rate, were different within the same type of cultivars, but showed no significant differences between types. Compared with the early-tall and dwarf cultivars that were released in earlier years, modern cultivars in semidwarf hybrid and super rice types had lower levels of chalkiness, setback value, and prolamin content in grains and significant higher breakdown value and contents of albumin, glutelin, lysine, glycine, and arginine. The continuously increasing grain yield with the evolution of cultivars was mainly attributed by the augment of spikelet number and grain number per panicle, which resulted from the large panicle trait. These results suggest that both quality and yield are improved during the evolution of mid-season indica rice cultivars.

摘 要以江苏省近60年来各阶段具有代表性的13个中熟籼稻品种(含杂交稻组合)为材料, 依据品种种植年代结合株型特点将其分为早期高秆、矮秆、半矮秆常规稻、半矮秆杂交稻和超级稻5个类型, 研究了品种演进过程中米质的变化。结果表明, 稻米的碾磨品质(糙米率、精米率和整精米率)在同一类品种间有较大差异, 在品种演进过程中无明显变化。与早期品种相比, 现代品种(半矮秆杂交稻和超级稻)稻米的垩白度显著降低, 崩解值变大, 消减值变小, 稻米中的清蛋白、谷蛋白、赖氨酸、甘氨酸和精氨酸含量显著增加, 醇溶蛋白含量显著降低。随着品种演进, 产量逐步提高, 其原因主要是总颖花量的增加及每穗粒数的显著增多。说明中籼水稻品种演进过程中, 米质和产量协同 提高。