Modelling virtual Riesling canopies for reducing sunburn risks in grapevine (Vitis vinifera L.) berries

众所周知，葡萄浆果和其他水果作物的晒伤是一种反复出现的疾病，会导致严重的产量损失和浆果质量下降。然而，近年来晒伤的出现有所增加。鉴于这些晒伤发生的观测结果通常与热浪有关，很可能在晒伤与气候变化之间存在联系。葡萄藤是研究气候变化影响的理想模型作物，这是第一个旨在调查未来葡萄园浆果晒伤相关性的模型研究。通过模拟葡萄园对环境条件变化的反应，我们可以了解气候变化对晒伤的影响。我们假设未来的气候条件可能会影响季节性晒伤的发生。例如，升高的CO2 （eCO2）可能会减少后期的晒伤风险，因为次生侧枝的生长增加。然而，随着更频繁的热浪，晒伤的发生，特别是与叶片脱落有关，可能会急剧增加。由于浆果晒伤是一种需要将浆果直接暴露在阳光下的疾病，它取决于葡萄藤树冠的结构。功能结构植物模型（FSPMs）详细地整合了冠层的结构元素，以捕捉冠层的变异性。虚拟雷司令是葡萄藤cv的FSPM。雷司令。它模拟了包括行方向在内的网格系统中树冠建筑的动态生长。事实证明，虚拟雷司令在评估温度变化对葡萄树结构的影响方面非常有用。我们假设可以从葡萄果实的三个关键特征来预测其晒伤的发生：局部日照、表面温度和对晒伤的易感性。所有的特点将被集成在一个先进的虚拟雷司令模型。为此，将开发和整合浆果和集群生长的新模型，包括浆果光传感器、浆果晒伤模型以及先进的三维叶片形状模型。新的子模型参数化和虚拟雷司令的进步将基于在葡萄园自由空气二氧化碳富集（FACE）设施中进行的实验。我们将进行一系列的室内实验，以评估对eCO2和温度升高的形态响应对晒伤发生的影响，并确定减少晒伤发生的最佳叶片去除措施。最后，我们将应用和比较两者，标准的叶片去除策略与新确定的策略理论上有利于减少现场晒伤风险。该项目的成果将帮助我们更好地了解气候变化如何影响晒伤，从而为减轻气候变化的影响提供新的思路，基于管理葡萄园和其他农业系统中的植物结构的新策略。

Sunburn in grapevine berries and other fruit crops is known as a recurring disorder causing severe yield losses and a decline in berry quality. Yet, an increased emergence of sunburn has been observed in recent years. Given that these observations of sunburn occurrence are often associated with heat waves, it is likely that there is a link between sunburn and climate change. Grapevine is an ideal model crop for studies of climate change impacts, and this is the first modelling study that aims at investigating the relevance of berry sunburn in future vineyards.Simulations of responses of vineyards to changes in environmental conditions should give us answers to the impact of climate change on sunburn. We hypothesize that future climatic conditions might affect seasonal sunburn occurrence. For example, elevated CO2 (eCO2) might reduce sunburn risks in the later season because of an increased growth of secondary lateral shoots. However, with more frequent heat waves sunburn occurrence, particularly re-lated to leaf removal, might dramatically increase. Since berry sunburn is a disorder that re-quires direct exposure of the berries to the sun, it depends on the grapevine canopy’s archi-tecture. Functional-structural plant models (FSPMs) integrate structural elements of a canopy in detail to catch the canopy’s variability. Virtual Riesling is such a FSPM for grapevine cv. Riesling. It simulates the dynamic growth of the canopy architecture within a trellis system including row orientation. Virtual Riesling has proven to be useful in assessing the significance of changing temperatures for grapevine architecture. We assume that sunburn occurrence of a grapevine berry can be predicted from three key characteristics of the berry: local sun-exposure, surface temperature and susceptibility to sunburn. All characteristics will be inte-grated in an advanced Virtual Riesling model. To this end, new models for berry and cluster growth including light sensors for berries, a model for berry sunburn, as well as an advanced three-dimensional leaf shape model will be developed and integrated. Parameterization of new sub-models and advancements of Virtual Riesling will be based on experiments con-ducted, inter alia, in a vineyard free-air carbon dioxide enrichment (FACE) facility. A series of in silico experiments will be performed to estimate the effects of morphological responses to eCO2 and increased temperature on sunburn occurrence and to identify optimized leaf re-moval practices for reducing sunburn occurrence. Finally, we will apply and compare both, standard leaf removal strategies versus the newly identified strategies theoretically favorable for reducing sunburn risks in the field.The project output will help us to better understand how climate change affects sunburn and will thus provide new ideas for mitigating effects of climate change, based on new strategies for managing plant architecture in vineyards and other agricultural systems.