不同年代玉米杂交种耐密性及其对深松增密的响应机制研究

发布时间：2018-06-28 22:08

本文选题：不同年代 + 玉米　；参考：《内蒙古农业大学》2017年硕士论文

【摘要】：选用耐密品种是提高玉米单产水平的有效途径之一。深松有利于改善土壤结构,促进根系下扎,提高作物对水分和养分的吸收和利用,延缓玉米植株衰老,增加产量。因此,为探索我国玉米品种更替过程对种植密度增加的适应性变化,进而探索玉米品种增密增产的机理,本研究选用不同年代玉米品种为试验材料,在深松及不同种植密度条件下,分析各品种的耐密性差异,揭示不同年代玉米杂交种耐密性的演变特点及差异性生理机制。同时,采取深松增密措施,研究不同年代玉米品种耐密性对深松的响应差异,进一步阐明耐密高产玉米品种对深松增密响应的生理机制。试验结果如下:(1)不同年代的玉米品种,随着年代的推进,增加种植密度以及深松后穗位叶叶夹角变小,叶向值升高,单株叶面积减少,从而使增密后的群体LAI增大。且不同年代玉米品种对深松增密反应有差异,近年代品种具有更好的耐密性。(2)不同年代的玉米品种,随着年代的推进,不同层位叶片SPAD值和叶片光合速率均表现为穗位叶上位叶下位叶。深松增密后,近年代的玉米品种有效延缓了增密后下位叶和穗位叶的衰老,提高了光合速率,有利于获得高产。(3)随着年代的推进,不同年代的玉米品种,玉米单株根系干重、根长、根表面积以及根系平均直径均呈现先上升后降低的单峰曲线变化趋势,随着年代的推进深层土壤(20-50cm)根系所占的比例明显增加,有利于在玉米根系总量减少的情况下使水分和养分得到充分的吸收和利用。(4)近代玉米品种在深松增密后根系构型优于之前的玉米品种,近年代玉米品种根系更细,对由于密度增加造成的根系干重、根长、根表面积降低的抗性增强,降幅低于其他年代玉米品种,同时深层土壤中根系干重、根长、根表面积所占比例增幅高于其他年代玉米品种。(5)不同年代的玉米品种,随着年代的推进,玉米单产呈升高的趋势,且表现为深松处理大于浅旋处理,高密度处理高于低密度处理,而在深松增密下,近年代的玉米品种由于具有更好的群体优势更易获得高产。因而,近代品种采用深松增密措施更易实现高产高效栽培。
[Abstract]:The selection of dense-tolerant varieties is one of the effective ways to improve the yield level of maize. Deep pine can improve soil structure, promote root system, increase the absorption and utilization of water and nutrients, delay senescence of maize plants and increase yield. Therefore, in order to explore the adaptive change of maize variety replacement process to the increase of planting density and the mechanism of increasing density and increasing yield of maize variety in China, different maize varieties of different ages were selected as experimental materials in this study. Under the condition of deep pine and different planting density, the differences of density tolerance of different varieties were analyzed, and the evolution characteristics and different physiological mechanism of density tolerance of maize hybrids of different ages were revealed. At the same time, the responses of different maize varieties to deep pine were studied by using deep pine density enhancement measures, and the physiological mechanism of density tolerance and high yield maize varieties' response to deep pine density enhancement was further elucidated. The results were as follows: (1) with the development of the age, the planting density and the angle between the leaves of the ear position became smaller, the leaf direction value increased, and the leaf area of the single plant decreased, which increased the population Lai after thickening. The responses of maize varieties in different ages to deep density enhancement were different, and the varieties in recent years had better densification tolerance. (2) with the development of age, maize varieties of different ages had better densification tolerance. The Spad value and photosynthetic rate of leaves in different layers were upper leaves of ear position and lower leaves of upper leaves. After deep loosening and thickening, maize varieties in recent years effectively delayed senescence of lower leaf and ear leaf after densification, increased photosynthetic rate, and gained high yield. (3) with the development of age, the dry weight of single plant root system of maize varieties of different ages was improved. The root length, root surface area and root mean diameter all showed the trend of single peak curve of first rising and then decreasing, and the proportion of root system in deep soil (20-50cm) increased obviously with the advance of age. It is propitious to absorb and utilize water and nutrients fully when the total amount of maize roots decreases. (4) the root system configuration of modern maize varieties is better than that of previous maize varieties after deep loosening and thickening, and the roots of maize varieties are finer in recent years. The resistance to root dry weight, root length and root surface area decrease due to density increase is lower than that of other maize varieties, while root dry weight and root length in deep soil, The percentage of root surface area was higher than that of other maize varieties. (5) with the advance of the age, the yield of maize per unit yield increased, and the deep loosening treatment was larger than the shallow spin treatment. The high density treatment was higher than the low density treatment, but under the condition of deep density enhancement, the maize varieties in recent years were more easy to obtain high yield because of the better population advantage. Therefore, it is easier to realize high-yield and high-efficient cultivation of modern varieties by using deep loosening and densification measures.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513

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