【摘要】 通过对河北省1975—2002年审(认)定夏播玉米杂交种主要农艺性状的分析,认为河北省夏播玉米杂交种主要农艺性状的演变规律是:株高和穗位有增高的趋势;果穗由细长形向短粗形(筒形)演变,穗粒数增多,千粒重则趋于稳定;株型由平展型逐渐向紧凑、半紧凑型演变;半硬粒型和硬粒型品种增多,马齿型品种的比例降低;产量水平稳步提高,递增幅度逐渐减少。品种的生育期有延长的趋势,适宜种植密度则在经历了由低到高的变化过程以后,近年又呈现逐渐回落的趋势。更多还原

【Abstract】 By the agronomic traits analysis of summer-planting hybrid maize varieties in Hebei province between 1975 and 2002, the development rule showed that the plant and ear position became higher; ear shape thin-long tended to grow thick; kernels per ear increased; 1000-grain weight tended to be stable; plant type changed from loose-type to compact-type or half -compact-type; flint and half flint varieties get more popular yet dent varieties became less; yield gradually increased but the range of yield improvement became lower. Variety growth period tended to be longer, the optimum density decreased gradually after a period in which it changed from low to high.更多还原