Can Changes in Canopy and/or Root System Architecture Explain Historical Maize Yield Trends in the US Corn Belt?
Can Changes in Canopy and/or Root System Architecture Explain Historical Maize Yield Trends in the US Corn Belt?
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DOI：
10.2135/cropsci2008.03.0152
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发表时间：
2009-01-01
期刊：
影响因子：
2.3
通讯作者：
Cooper, Mark
中科院分区：
文献类型：
--
作者：
Hammer, Graeme L.;Dong, Zhanshan;Cooper, Mark
美国玉米产量的持续增长与植株密度的相互作用有关。已经提出了一些促成的特征和机制。在这项研究中，我们使用建模方法来检验冠层和/或根系结构的变化是否可以解释观察到的趋势。本文对玉米作物模型进行了推广，以便研究冠层和根系结构的变化。提出了一种分层的、逐日变化的冠层光合作用模型来预测冠层结构变化的后果。提出了一种二维根系探测模型，用于预测根系结构变化的后果。通过田间试验，推导了先锋3394基础杂交品种的模型参数。对不同地点、土壤和密度的树冠和根系结构进行了模拟研究。模拟对密度的响应与现场实验的结果比较好。分析表明：(1)根系构型和水分捕获的变化对生物量积累和历史产量趋势有直接影响；（ii）冠层结构的变化对作物的直接影响不大，但可能通过叶面积保留和碳水化合物分配到穗部产生重要的间接影响。该研究为未来的研究和作物改良工作提供了合理的解释和可验证的假设。
Continuous increase in the yield of maize (Zea mays L.) in the U.S. Corn Be-It has involved an interaction with plant density. A number of contributing traits and mechanisms have been suggested. In this Study we used a modeling approach to examine whether changes in canopy and/or root system architecture might explain the observed trends. A maize crop model was generalized so that changes in canopy and root system architecture could be examined. A layered, diurnal canopy photosynthesis model was introduced to predict consequences of change in canopy architecture. A two-dimensional root exploration model was introduced to predict consequences of change in root system architecture. Field experiments were conducted to derive model parameters for the base hybrid (Pioneer 3394). Simulation studies for various canopy and root system architectures were undertaken for a range of sites, soils, and densities. Simulated responses to density compared well with those found in field experiments. The analysis indicated that (i) change in root system architecture and water capture had a direct effect on biomass accumulation and historical yield trends; and (ii) change in canopy architecture had little direct effect but likely had important indirect effects via leaf area retention and partitioning of carbohydrate to the ear, The study provided plausible explarations and identified testable hypotheses for future research and crop improvement effort.