Department of Vegetable and Field Crops, Institute of Plant Sciences, Agricultural Research Organization, The Volcani Institute, Rishon LeZion, 7505101, Israel.
The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel.
BMC Plant Biol. 2024 Sep 30;24(1):896. doi: 10.1186/s12870-024-05575-7.
Populations of Olea europaea subsp. europaea var. sylvestris, the ancestor of cultivated olives, are scattered across the Mediterranean Basin. However, after millennia of possible hybridization with cultivated varieties, the genetic identity of many of these populations remain questionable. In the southern Levant, the plausible primary domestication center of olives, many of the naturally growing olive (NGOs) are considered feral, having developed from nearby olive groves. Here, we investigated the genetic identity of NGOs population in the Carmel region, hypothesizing that their specific location, which limit anemophily, provided an opportunity for the persistence of genuine var. sylvestris.
We mapped more than 1,000 NGOs on the Kurkar ridge along the Carmel coast, within and outside the residential area of Atlit and used simple sequence repeats of 14 loci to assess the spatial genetic structure of 129 NGOs. Genetic diversity parameters and genetic distances between NGO and cultivated olives, as well as phenotypic and morphometric analyses of their oil content and pits, respectively, indicated the presence of a genuine var. sylvestris population. However, NGOs within the residential area of Atlit and old settlements showed an intermediate admix genetic structure, indicating on hybridization with local varieties, a consequence of their proximity to cultivated trees.
Integrating the results of genetic and phenotypic analyses we provide crucial evidence of the presence of a genuine var. sylvestris population in the southern Levant, in close geographical proximity to archaeological sites with the earliest evidence of olive exploitation in the ancient world. We supplement the results with recommendations for a conservation program that combines municipal requirements and the urgent need to preserve the largest population of var. sylvestris in the southern Levant.
油橄榄亚种欧洲变种欧洲亚种的种群，即栽培橄榄的祖先，分散在地中海盆地各地。然而，在与栽培品种可能杂交的几千年后，许多这些种群的遗传身份仍然存在疑问。在地中海东南部，橄榄的可能的原始驯化中心，许多自然生长的橄榄（NGOs）被认为是野生的，是由附近的橄榄林发展而来的。在这里，我们研究了卡梅尔地区 NGOs 种群的遗传身份，假设它们的特定位置，限制了风媒传粉，为真正的 var sylvestris 的持续存在提供了机会。
我们在卡梅尔海岸的 Kurkar 山脊上绘制了超过 1000 个 NGOs 的位置，包括阿提特居民区内外，并使用 14 个基因座的简单序列重复来评估 129 个 NGOs 的空间遗传结构。NGO 与栽培橄榄之间的遗传多样性参数和遗传距离，以及它们油含量和坑的表型和形态计量分析，分别表明存在真正的 var sylvestris 种群。然而，阿提特居民区和旧定居点内的 NGOs 表现出中间混合遗传结构，表明与当地品种发生了杂交，这是它们靠近栽培树木的结果。
综合遗传和表型分析的结果，我们提供了在地中海东南部存在真正的 var sylvestris 种群的关键证据，该种群与古代世界最早的橄榄开发考古遗址在地理上非常接近。我们补充了建议保护计划的结果，该计划结合了市政要求和保护地中海东南部最大的 var sylvestris 种群的迫切需要。
