玉米播期推迟与生长发育、有效积温关系研究

Relations Between Delayed Sowing Date and Growth,Effective Accumulated Temperature of Maize

试验选用先玉335、郑单958和浚单20为供试品种,从5月6日至6月7日共设7个播期,研究春旱条件下玉米播期推迟与生长发育、有效积温的关系。结果表明,随播种期推迟各阶段生育进程加快,播种期推迟30 d,播种至出苗天数缩短4 d;出苗至抽雄天数各品种间表现不同,先玉335缩短11 d,郑单958缩短8 d,浚单20缩短3 d。随播期的推迟株高和穗位高增高,总叶片数和穗上叶片数不变;秃尖增长,行粒数减少,穗长、穗粗和穗行数不变;子粒长度减小,宽度不变,千粒重和容重降低,播期对千粒重的影响大于容重。产量与玉米生长期有效积温呈正相关,浚单20的相关系数最大,其次是先玉335,郑单958最小。研究结果表明,浚单20播期最迟为5月16日(有效积温2752.9℃.d),先玉335播期最迟为5月23日(有效积温2624.4℃.d),郑单958播期最迟可至5月27日(有效积温2560.9℃.d)。

Seven sowing dates（Days from May 6 to June 7） and three species（Xianyu335, Zhengdan958 and Xun dan20） were used to investigate the relations between delayed sowing date and growth, effective accumulated tempera ture of maize under drought conditions in spring. The results showed that with the delay of sowing date, the growing process of various stages accelerated. Sowing date delayed 30 days, sowingemergence was 4 days shorter, emer gencetasseling days of every varieties was different, Xianyu335 was 11 days shorter, Zhengdan958 was 8 days shorter and Xundan20 was 3 days shorter. Xianyu335 grew rapidly under the late sowing date conditions, so as to try to get relatively long times for its postfilling. With the delay of sowing date, plant height and ear height increased, the num ber of total leaves and ear leaves was the same, bald increased, kernel numbers per row decreased, panicle length, panicle diameter and row numbers per ear unchanged, grain length decreased and grain width was the same, 1 000 kernel weight and unit weight decreased, the effects of sowing date on grain weight is greater than the unit weight. Production was positively correlated with the effective accumulated temperature of maize growing period, and the cor relation coefficient of Xundan20 was thelargest, the next one was Xianyu335, Zhengdan958 was the least. The analysis showed that the latest sowing date of Xundan20 was May 16, Xianyu335 was May 23 and Zhengdan958 was May 27.