摘要：

播期和密度是影响玉米产量的2个关键因素。为明确不同玉米品种在黄淮海地区对夏播播期和密度的响应特征,以中农大788和科河699为试验材料,设置6月10日、17日、24日3个播期,以及67 500(A),75 000(B),82 500(C)株/hm² 3个播种密度,调查其生育进程、形态指标、产量及产量构成因素。结果表明,随着播期推迟,玉米吐丝前的生育进程加快,籽粒灌浆期延长,第3播期(6月24日)的籽粒无法正常成熟。晚播(第3播期)相较于早播(第1播期即6月10日),中农大788穗位高和科河699株高、穗位高均显著增加,2个品种茎粗均显著减小;2个品种空秆率和倒伏率均随播期推迟而增加;中农大788主要由于千粒质量降低,导致产量降低21.8%,科河699穗数、穗粒数、千粒质量均显著降低,导致减产41.3%。密度C较密度A,2个品种株高、穗位高、空秆率、倒伏率均显著增加,茎粗则显著减小。中农大788在密度B获得最大产量且显著高于密度A,分别为12 450,11 097 kg/hm²。随密度增加科河699空秆率增加,导致穗数并未显著增加,穗粒数减少,密度C较密度A产量显著降低,分别为7 548,9 464 kg/hm²。播期密度互作仅对倒伏率有极显著影响,对植株形态指标、空秆率、产量及产量构成因素影响不显著。综合来看,中农大788平均产量高于科河699,前者在晚播和高密条件下空秆和倒伏率低,产量更稳定。实际生产中,夏玉米应尽量早播,晚播可通过选择适宜的品种减少产量损失,选育耐密品种是增密增产的关键。

关键词: 夏玉米, 品种, 播期, 密度, 产量, 生长发育特性

Abstract:

Sowing date and Planting density are two key factors that affect maize yield.In order to clarify the response characteristics of different summer maize cultivars to sowing date and planting density in the Huanghuaihai region.Two maize cultivars Zhongnongda 788 and Kehe 699 were used as test materials.Three sowing dates,June 10,17 and 24,as well as three densities,67 500(A),75 000(B),and 82 500 plants/ha(C)were set and later investigated the growth stages,morphological indexes,yield and yield components.The results showed that the growth process before silking was accelerated and the filling period was prolonged as the sowing dates postponed,maize planted in the third sowing date could not reach physiological maturity.Late sowing date(the third sowing date June 24)compared to early sowing date(the first sowing date June 10),the ear height of Zhongnongda 788 and the plant height,ear height of Kehe 699 increased significantly.The stem diameters of the two cultivars were significantly reduced;the empty stalk and lodging rate of the two cultivars increased with the delayed sowing dates;the yield of Zhongnongda 788 decreased by 21.8% mainly due to the decrease of 1000-kernel weight,the yield of Kehe 699 decreased by 41.3% due to significant reduction of ear number,kernel number per ear and 1000-kernel weight.Compared to density A,the plant height,ear height,empty stalk rate and lodging rate of the two cultivars increased significantly,the stem diameter decreased in density C significantly.Zhongnongda 788 obtained the maximum yield at density B and was significantly higher than density A,which were 12 450,11 097 kg/ha,respectively.With the increase of density,ear number of Kehe 699 didn't increased due to increased empty stalk rate,kernel number per ear decreased,thus yield of density C was significantly lower than density A,which were 7 548,9 464 kg/ha respectively.Interaction between sowing date and density only had extremely significant effect on lodging rate,but had no significant effects on morphological indexes,empty stalk rate,yield and yield components.On the whole,the average yield of Zhongnongda 788 was higher than Kehe 699,the former had lower empty stalk rate,lodging rate and more stable yield under the conditions of late sowing date and high density.In practical production,summer maize should be sown as early as possible,the yield loss caused by late sowing can be reduced by selecting suitable cultivars.To improve yield by increasing density,density resistance cultivar breeding is necessary.

Key words: Summer maize, Cultivar, Sowing date, Planting density, Yield, Growth and development characteristics