GROUNDNUT GROWTH AND DEVELOPMENT IN CONTRASTING ENVIRONMENTS. 2. HEAT UNIT ACCUMULATION AND PHOTO-THERMAL EFFECTS ON HARVEST INDEX
GROUNDNUT GROWTH AND DEVELOPMENT IN CONTRASTING ENVIRONMENTS. 2. HEAT UNIT ACCUMULATION AND PHOTO-THERMAL EFFECTS ON HARVEST INDEX
复制标题
对比环境中的花生生长和发育。
作者：
M. Bell;G. Wright
当相同品种的花生（Arachishypogaea）在各种环境条件下生长时，温度和辐照度在决定作物持续时间和干物质到豆荚的分配方面发挥着重要作用，后者通过收获指数进行评估。利用已发表的弗吉尼亚花生品种 Early Bunch 在非限制条件下的数据，我们表明，使用三个基本温度（Tb=9 °C、To=29 °C 和 Tm=39 °C）积累热时间对于预测作物成熟度具有相当大的潜力。在从印度尼西亚的湿润热带地区到澳大利亚的高亚热带地区的 16 次播种中，Early Bunch 的收获日期相当于播种后 1808（±23）度日的积累。除半干旱热带地区的播种外，在所有播种中，该热时间值均在实际收获成熟后的八个日历日内。收获指数随地点和播种日期的不同而变化很大，范围从 0.31（印度尼西亚）到 0.58（亚热带澳大利亚）。使用生长季节期间的总短波太阳辐射事件和计算的热时间值，用光热商（PTQ，MJ m−2 度-天−1）描述每个地点每次播种的生长季节。 PTQ 的值范围为 0.99（印度尼西亚）至 2.11（亚热带澳大利亚）。收获指数的变化很大程度上可以通过 PTQ 的曲线函数（R2=0.98）来解释，前提是数据不会受到光周期影响的影响。在半干旱热带环境中，与延迟播种相关的光周期减少是控制收获指数的主导因素。
When the same cultivars of groundnuts (Arachis hypogaea) were grown under a wide range of environmental conditions, temperature and irradiance played a major role in determining crop duration and partitioning of dry matter to pods, the latter assessed by harvest index. Utilizing published data for the Virginia groundnut cultivar Early Bunch under non-limiting conditions, we show that accumulation of thermal time using three cardinal temperatures (Tb=9 °C, To=29 °C and Tm=39 °C) has considerable potential for predicting crop maturity. In sixteen sowings ranging from the wet tropics in Indonesia to the elevated subtropics in Australia, harvest date for Early Bunch corresponded to the accumulation of 1808 (±23) degree-days after sowing. In all sowings except one in the semi-arid tropics, this value of thermal time was within eight calendar days of actual harvest maturity. Harvest index varied greatly with both location and sowing date, ranging from 0.31 (Indonesia) to 0.58 (subtropical Australia). Using total short-wave solar radiation incident during the growing season and calculated values of thermal time, the growing season for each sowing in each location was described in terms of a photo-thermal quotient (PTQ, MJ m−2 degree-day−1). Values for PTQ ranged from 0.99 (Indonesia) to 2.11 (subtropical Australia). Variation in harvest index could be explained largely by a curvilinear function of PTQ (R2=0.98), provided data were not confounded by the effects of photoperiod. In the semi-arid tropical environment, decreases in photoperiod associated with delayed sowing were the dominant factor controlling harvest index.