The sustainability of silvoarable agroforestry systems largely depends on the choice of suitable crop species and varieties for minimizing competitive interactions in the interaction zone with trees. Up to date crop intraspecific variability has been poorly investigated, and mainly in pot trials under artificial shading. Given this framework, a trial was conducted in field conditions in NE Italy to study the response of 10 common wheat varieties cultivated in the 6-m narrow inter-row of a specialized 4-year old poplar plantation (AF, agroforestry) vs. full sun conditions (C, controls). Here it was demonstrated that large genetic variability exists in wheat, as grain yield reductions under shading ranged between 31 and 75% (average − 57%) depending on variety choice. Better tolerance was highlighted in old varieties (− 44% of yield in AF vs. C), that was associated to greater plasticity in delaying leaf senescence, and increased both leaf area index and SPAD (index of chlorophyll content), while achieving the highest grain protein contents (> 17.3% DW). However, under shading modern wheat varieties still remained the highest yielding, particularly in bread-making varieties (469 g m⁻² on average), thanks to larger improvement of the leaf-to-culm biomass ratio and better harvest index. We conclude that there is large scope for identifying wheat varieties suitable for agroforestry systems, while breeding programs can select for specific morpho-physiological adaptation traits to low irradiance.

造林农林业系统的可持续性在很大程度上取决于选择合适的作物品种和品种，以尽量减少与树木相互作用区的竞争性相互作用。迄今为止，对作物种内变异的研究很少，而且主要是在人工遮荫下的盆栽试验中。在此框架下，我们在意大利东北部的田间条件下进行了一项试验，研究在专门的 4 年生杨树种植园（AF，农林业）的 6 米窄行间种植的 10 种普通小麦品种与全田种植的反应阳光条件（C，对照）。研究表明，小麦存在很大的遗传变异，根据品种选择，遮荫下的谷物产量减少了 31% 至 75%（平均 - 57%）。老品种具有更好的耐受性（AF 相对于 C 产量高出 44%），这与延缓叶片衰老的更大可塑性相关，并且叶面积指数和 SPAD（叶绿素含量指数）均有所增加，同时达到了最高值谷物蛋白质含量（> 17.3% DW）。然而，在遮荫下，由于叶秆生物量比的较大改善和更好的收获指数，现代小麦品种仍然保持最高产量，特别是面包制作品种（平均469 g m ^-2 ）。我们的结论是，识别适合农林业系统的小麦品种有很大的空间，而育种计划可以选择特定的形态生理适应低辐照度的性状。