不同熟期夏玉米品种籽粒灌浆与脱水特性及其密度效应

研究不同熟期夏玉米品种籽粒灌浆与脱水特性及种植密度的调控作用,以期为黄淮海地区夏玉米籽粒机收提供科学依据。2016—2017年在山东农业大学玉米科技创新园,种植早熟玉米品种登海518 (DH518)、衡早8号(HZ8)和中晚熟玉米品种郑单958 (ZD958)、登海605 (DH605),设60 000、75 000、90 000株hm~(–2) 3个种植密度。结果表明,早熟品种DH518、HZ8较中晚熟品种ZD958、DH605灌浆期短,产量低。4个品种生理成熟时的籽粒含水率与其生育期相关性不显著,早熟品种籽粒后期脱水速率快,DH518和HZ8从籽粒达最大含水量到生理成熟的脱水速率均值较ZD958和DH605两年分别高0.015%°C~(–1)和0.014%°C~(–1)。相关性分析显示,籽粒脱水速率与灌浆速率相关性不显著,生育后期籽粒含水率与茎鞘、叶片含水率呈显著正相关,与苞叶、穗轴含水率呈极显著正相关。随种植密度的增加,不同品种籽粒灌浆期缩短,平均灌浆速率降低,籽粒生理成熟时的含水率降低。合理增加种植密度能够显著提高不同熟期夏玉米品种的产量。

Grain Filling and Dehydration Characteristics of Summer Maize Hybrids Differing in Maturities and Effect of Plant Density

Exploring grain-filling and dehydration characteristics of summer maize hybrids differing in maturities and the regulation function of plant density, could provide theoretical and technical reference for the mechanized grain harvest in The Yellow- Huaihe-Haihe Rivers plain region. A field experiment was conducted from 2016 to 2017, using early hybrids Denghai 518 (DH518), Hengzao 8 (HZ8) and middle-late hybrids Zhengdan 958 (ZD958), Denghai 605 (DH605) with three plant densities of 60 000, 75 000, and 90 000 plants ha ^-1. The grain-filling duration was shorter and the yield was lower in early hybrids DH518, HZ8 than in middle-late hybrids ZD958, DH605. Grain moisture content of the four hybrids at physiological maturity had no significant correlation with their growth period duration. Compared with middle-late hybrids, grain dehydration rate of early hybrids at late growth stage was faster. In 2016 and 2017, mean value of grain dehydration rate from the date reaching maximum grain water content to physiological maturity of DH518 and HZ8 was 0.015% °C ^-1 and 0.014% °C ^-1 higher than that of ZD958 and DH605 respectively. The grain dehydration rate had no significant correlation with filling rate, the moisture content in grain at late growth stage was positively correlated with that in stem, sheath and leaf at P < 0.05, and with that in bract and cob at P < 0.01. With increasing plant density, grain-filling duration of different summer maize hybrids become shorter, average filling rate reduced, and grain moisture content at physiological maturity reduced. Reasonably increasing plant density could significantly improve the yield of summer maize hybrids differing in maturities.