McMaster Gregory S, White Jeffrey W, Hunt L A, Jamieson P D, Dhillon S S, Ortiz-Monasterio J I
USDA-ARS, Agricultural Systems Research, 2150 Centre Avenue, Building D, Suite 200, Fort Collins, CO 80526, USA.
Ann Bot. 2008 Oct;102(4):561-9. doi: 10.1093/aob/mcn115. Epub 2008 Jul 15.
Accurately representing development is essential for applying crop simulations to investigate the effects of climate, genotypes or crop management. Development in wheat (Triticum aestivum, T. durum) is primarily driven by temperature, but affected by vernalization and photoperiod, and is often simulated by reducing thermal-time accumulation using vernalization or photoperiod factors or limiting accumulation when a lower optimum temperature (T(optl)) is exceeded. In this study T(optl) and methods for representing effects of vernalization and photoperiod on anthesis were examined using a range of planting dates and genotypes.
An examination was made of T(optl) values of 15, 20, 25 and 50 degrees C, and either the most limiting or the multiplicative value of the vernalization and photoperiod development rate factors for simulating anthesis. Field data were from replicated trials at Ludhiana, Punjab, India with July through to December planting dates and seven cultivars varying in vernalization response.
Simulations of anthesis were similar for T(optl) values of 20, 25 and 50 degrees C, but a T(optl) of 15 degrees C resulted in a consistent bias towards predicting anthesis late for early planting dates. Results for T(optl) above 15 degrees C may have occurred because mean temperatures rarely exceeded 20 degrees C before anthesis for many planting dates. For cultivars having a strong vernalization response, anthesis was more accurately simulated when vernalization and photoperiod factors were multiplied rather than using the most limiting of the two factors.
Setting T(optl) to a high value (30 degrees C) and multiplying the vernalization and photoperiod factors resulted in accurately simulating anthesis for a wide range of planting dates and genotypes. However, for environments where average temperatures exceed 20 degrees C for much of the pre-anthesis period, a lower T(optl) (23 degrees C) might be appropriate. These results highlight the value of testing a model over a wide range of environments.
准确描述作物发育对于应用作物模拟模型来研究气候、基因型或作物管理的影响至关重要。小麦（普通小麦、硬粒小麦）的发育主要受温度驱动，但也受春化作用和光周期影响，通常通过使用春化或光周期因子减少热时间积累或在超过较低的最适温度（T(optl)）时限制积累来进行模拟。在本研究中，利用一系列播种日期和基因型对T(optl)以及表示春化作用和光周期对抽穗影响的方法进行了研究。
研究了15、20、25和50℃的T(optl)值，以及用于模拟抽穗的春化和光周期发育速率因子的最限制值或乘积值。田间数据来自印度旁遮普邦卢迪亚纳的重复试验，播种日期从7月至12月，有7个春化反应不同的品种。
20、25和50℃的T(optl)值对抽穗的模拟结果相似，但15℃的T(optl)导致对早播日期预测抽穗延迟存在一致偏差。T(optl)高于15℃出现这种结果可能是因为许多播种日期在抽穗前平均温度很少超过20℃。对于春化反应强烈的品种，当春化和光周期因子相乘而不是使用两者中最限制的因子时，抽穗模拟更准确。
将T(optl)设定为较高值（30℃）并将春化和光周期因子相乘，可准确模拟广泛播种日期和基因型的抽穗情况。然而，对于抽穗前期大部分时间平均温度超过20℃的环境，较低的T(optl)（23℃）可能更合适。这些结果凸显了在广泛环境中测试模型的价值。
