内蒙古平原灌区超高产春玉米品种对深松再增密响应的耐密生理机制

Maize grown in plain irrigated regions of Inner Mongolia has the light-temperature production potential to catch up with and surpass the world levels in unit yield. The relatively low density-tolerant property of maize varieties and the topsoil that is shallow, hard and lacking restrict to play improving yield potential by increasing planting densities for super high-yield spring maize.To break the yield bottle neck by subsoiling, and achieve the goal of large area of super high-yield and further make breakthrough for super high-yield. We will use the spring maize varieties of different ages, super high-yield and American high-yield as test material, and take subsoiling and shallow rotary tillage cultivation measures, different planting densities, different ecological regions, to study the density-tolerant physiological mechanism of responding to further increasing planting density in subsoiling condition about the super high-yield spring maize. In this study, We will (1) show the law of succession on density-tolerance and its responding to further increaseing planting density under subsoiling condition in the process of spring maize varieties evolution.(2) indicate the similarities and differences between Chinese and American high-yield maize varieties about density-tolerance and its responding to further increaseing the planting density in subsoiling condition.(3) clarify the physiological mechanism of density-tolerance and its responding to further increaseing planting density under subsoiling condition about super high-yield spring maize varieties.(4) proved the limiting factor and the regulation pathway for super high-yield spring maize to increase yield by further increasing the planting density under subsoiling condition. Finally we will provide theoretical basis and techniques for achieveing the large area super high-yield and further make breakthrough for super high-yield by further increasing planting density under subsoiling condition in irrigated plain region of Inner Mongolia.

立足于内蒙古平原灌区具有赶超世界玉米单产水平的光温生产潜力和优势，针对超高产春玉米生产中品种自身耐密性低或耕层浅、实、少而导致品种的增密增产潜力发挥受限的瓶颈问题，以深松改土实现大面积高产和再增密增产挖潜的超高产突破为目标。以不同年代春玉米品种、美国高产玉米品种和我国超高产春玉米品种为试验材料，在常规浅旋耕和深松处理，不同种植密度，不同生态区域条件下，开展超高产春玉米品种对深松再增密响应的耐密生理机制研究。(1)揭示不同年代春玉米品种耐密性及其对深松再增密响应的演替变化规律；(2)明确我国与美国超高产春玉米品种耐密性及对深松再增密响应的异同性；（3）阐明超高产春玉米耐密性及其对深松再增密响应的生理机制；（4）探明不同耐密类型超高产春玉米深松再增密增产的限制因子及其调控途径。为深松改土再增密实现大面积超高产和超高产再突破提供理论依据和技术途径。

本项目立足于内蒙古平原灌区具有赶超世界玉米单产水平的光温生产潜力和优势，针对超高产春玉米生产中品种自身耐密性低或耕层浅、实、少而导致品种的增密增产潜力发挥受限的瓶颈问题，以深松改土实现大面积高产和再增密增产挖潜的超高产突破为目标。以不同年代春玉米品种、美国和德国高产玉米品种和我国超高产春玉米品种为试验材料，在常规浅旋耕和深松处理，不同种植密度梯度，不同生态区域条件下，开展超高产春玉米品种对深松再增密响应的耐密生理机制研究。通过对不同处理下土壤-根系-冠层-产量-生态等指标的系统分析，(1)明确不同年代春玉米品种随着年代的推进由于其根系冠层结构功能的优化耐密性增强，产量提高，现代品种对深松的响应更加敏感，深松的调控效果更好；(2)阐明了我国与美国和德国高产春玉米品种在根系和冠层结构功能上均存在显著的差异，深松后差异更加明显，是导致我国玉米品种耐密性及其对深松再增密响应异同的主要原因；（3）明确了茎粗、相对SPAD值等等7个指标可作为耐密性强弱的评价指标，并以其建立了归一化的变异系数作为权重的模糊隶属函数玉米耐密性综合评价方法；（4）阐明超高产玉米再增密后根系干重、花后、群体LAI、穗位叶LTP、底层叶LTP、群体干物质积累量等大幅度降低是限制不同耐密性超高产春玉米增密增产的主要因素，深松后可显著改善单株和群体结构功能，最高产量的种植密度可提高1.5万株/hm2，最高产量提高1.08 t/hm2~1.94t/ hm2；（5）探明花后日温差<10℃天数、花后日照时数<8h天数、花后日均温度和土壤中速效磷含量是造成玉米品种对深松响应区域间差异的主要因素，强耐密性品种的深松调控效果在区域间更稳定。. 研究结果共发表论文11篇。其中，SCI 1篇，核心期刊6篇；审定地方标准1项；获得内蒙古自治区科技进步二等奖1项，颁布地方标准1项，编辑出版技术挂图7幅。为选育耐密高产适宜深松耕作的玉米品种，以及通过深松改土再增密实现大面积超高产和超高产再突破提供理论依据和技术途径。