【作者】 张倩；

【导师】 段留生；

【作者基本信息】 中国农业大学 ， 作物栽培学与耕作学， 2014， 博士

【摘要】 倒伏是限制玉米产量进一步提高的重要因素,近年来我国发生过多次大面积倒伏现象。本研究在黑龙江省寒地春玉米种植区进行,以玉米杂交种郑单958和先玉335为材料,研究了不同密度与氮肥水平下植物生长调节剂对玉米茎秆质量和产量的调控,建立玉米倒伏预测模型。主要的研究结果如下：(1)随着种植密度的增加,植株冠层结构与光合系统下降,节间抗折力降低,田间倒伏率增加；平方米穗数显著增加,穗粒数和千粒重显著降低,产量在75000株hm-2的密度下达到最高,且密度与品种存在显著的互作效应。30%己·乙水剂改善了中高密度下植株冠层结构,提高了第3节间的抗折力,降低倒伏率；合理调控了叶片与茎秆的碳氮运转率,从而更提高了75000株hm-2密度的玉米产量。30%己·乙水剂、密度与品种对玉米产量形成与倒伏的调控有互作效应。(2)随氮肥施用量增加,玉米冠层结构下降,基部第3节间碳氮比和抗折力下降。其中,中氮肥量180kghm-2促进了叶片的碳氮运转,增加了穗粒数,从而显著地提高了产量。30%己·乙水剂改善了中氮水平下的冠层结构与光合作用,提高了第3节间的抗折力,同时进一步提高了产量。30%己·乙水剂、氮肥与品种对玉米产量形成无显著的互作效应。(3)根据植株形态及节间性状,构建了玉米倒伏的多元线性回归模型y=24.40112+0.31213x1+0.23863x2+0.15592x3-0.37010x4-0.12414x5-0.01177x6。另外,根据植株力学结构,并结合风的作用,初步推导出了玉米生物力学的倒伏指数方程,能够评价不同植株的倒伏风险；同时反映出不同品种、化控处理、栽培措施等因素的倒伏差异,可以为生产上选择合理的品种与栽培方式提供理论依据。(4)于玉米拔节初期叶面喷施新磷酸盐化合物(DHEAP)的水溶液能够降低玉米株高和穗位高,显著缩短基部节间长度,增加节间直径；同时该调节剂能够增强玉米基部第2和3节间的抗折力,降低田间倒伏率；600mL hm-2处理使产量增加的幅度达30%～8%。综上所述,郑单958和先玉335分别在最适的种植密度60000和75000株hm-2及氮肥水平180kghm2下,应用30%己·乙水剂,能进一步提高产量,同时改善了玉米株型,增加了玉米的抗倒伏能力,是寒地春玉米的最佳种植模式。本研究为寒地春玉米高产栽培的建立及玉米倒伏的预测提供理论依据。更多还原

【Abstract】 Lodging is one of the most important limiting factors to further increase yield. There were several lodging happened of large areas in China.This study was conducted in Heilongjiang province which belongs to cold spring maize belt, Zhengdan958and Xianyu335were materials, the objectives of the study were:effect of plant growth regulator (PGR) on maize stem quality, lodging and yield under different plant densities and nitrogen fertilizer levels; to establish maize biomechanics lodging model; The main results were as follows:(1) With the increase of plant density, the canopy structure and photosynthesis became deteriorated; lodging rate was increased. The number of ears per unit ground area increased linearly with plant density, but number of kernels per ear and kernel weight showed decreased, the yield showed a peak at intermediate plant density of75000plant ha’1. There was a significant interaction between plant density and cultivar. Plant growth regulator30%Hex-ethyl-aqua improved canopy structure and photosynthesis, increased3internode strength of breaking-resistance and decreased lodging rate at higher plant density.30%Hex-ethyl-aqua also regulated carbon translocation rate of leaf and stem. Application of PGR increased the yield of two maize by increasing thousand-kernel weight (TKW) and kernels per ear.(2) In the study of nitrogen application, the canopy structure weakened and the length of basal3rd were increased with the increase of nitrogen application. The ratio of carbon and nitrogen in internode and strength of breaking-resistance were decreased with the increase of nitrogen application. Medium application of nitrogen (180kg hm"2) could improve the structure of canopy and increase yield. Under the180kg hm’2nitrogen level,30%Hex-ethyl-aqua improved canopy structure and photosynthesis, increased3rd internode strength of breaking-resistance and yield. There were not significant interactions between30%Hex-ethyl-aqua, plant density and cultivar on yield and components.(3) The multiple linear regression model between lodging and plant height, ear height and the strength of breaking-resistance of2nd to5th internode was deduced, y=24.40112+0.31213xi+0.23863x2+0.15592x3-0.37010X4-0.12414x5-0.01177Xe. Analysis of mechanics and plant morphology under the wind force, and to preliminary built biomechanic equation of maize lodging index (MLI). This MLI can evaluate lodging risk of plant and reflect the differences of HK, hybrids and cultivation ways on lodging. And this can provide theoretical basis for selection reasonable cultivars and cultivation ways under field production.(4) Application of a novel plant growth regulator DHEAP solution through spraying leaves at early jointing stage (V7). Plant height was decreased, ear height and basal internodes length were significantly shortened, internodes diameter were increased, and there were an obvious dose effect relationships. The strength of breaking-resistant of2nd and3rd internodes was improved so that increasing the ability of resistant lodging and decreased lodging rate. The yield was increased by3%-8%under the treatment of600mL hm-2. In a word, our results demonstrate that application of30%Hex-ethyl-aqua under the medium nitrogen (180kg hm-2) and medium plant density condition is the optimum cultivation practice in maize of cold region due to the best yield, plant morphology, population structure and lodging resistance force. Overall, this research provided theoretical basis for the establishment of the high-yield cultivation and the prediction of maize lodging.更多还原