Wehenkel Christian, Mariscal-Lucero Samantha Del Rocío, González-Elizondo M Socorro, Aguirre-Galindo Víctor A, Fladung Matthias, López-Sánchez Carlos A
Instituto de Silvicultura e Industria de la Madera, Universidad Juárez del Estado de Durango, Durango, Mexico.
Instituto Tecnológico del Valle del Guadiana, Tecnológico Nacional de México, Durango, Mexico.
PeerJ. 2020 Feb 26;8:e8648. doi: 10.7717/peerj.8648. eCollection 2020.
and are endemic to western Mexico, where they cover an area of more than 1 million hectares. is also cultivated in field trials in South Africa and South America, because of its considerable economic importance as a source of timber and resin. Seed quality, afforestation success and desirable traits may all be influenced by the presence of hybrid trees in seed stands.
We aimed to determine the degree of hybridization between . and . in seed stands of each species located in the Sierra Madre Occidental, Durango, Mexico.
AFLP molecular markers from samples of 171 trees across five populations were analyzed with STRUCTURE and NewHybrids software to determine the degree of introgressive hybridization. The accuracy of STRUCTURE and NewHybrids in detecting hybrids was quantified using the software Hybridlab 1.0. Morphological analysis of 131 samples from two populations of and two populations of was also conducted by Random Forest classification. The data were compared by Principal Coordinate Analysis (PCoA) in GenAlex 6.501.
Hybridization between and was observed in all seed stands under study and resulted in enhancement of desirable silvicultural traits in the latter species. In , only about 16% molecularly detected hybrids correspond to those identified on a morphological basis. However, the morphology of is not consistent with the molecularly identified hybrids from one population and is only consistent with 3.3 of those from the other population.
This is the first report of hybrid vigour (heterosis) in Mexican pines. Information about hybridization and introgression is essential for developing effective future breeding programs, successful establishment of plantations and management of natural forest stands. Understanding how natural hybridization may influence the evolution and adaptation of pines to climate change is a cornerstone to sustainable forest management including adaptive silviculture.
[具体树种1]和[具体树种2]原产于墨西哥西部，分布面积超过100万公顷。由于其作为木材和树脂来源具有相当大的经济重要性，[具体树种2]也在南非和南美洲进行田间试验种植。种子林分中杂交树的存在可能会影响种子质量、造林成功率和理想性状。
我们旨在确定位于墨西哥杜兰戈西马德雷山脉的每个物种的种子林分中[具体树种1]和[具体树种2]之间的杂交程度。
使用STRUCTURE和NewHybrids软件对来自五个种群共171棵树的样本的AFLP分子标记进行分析，以确定渐渗杂交程度。使用Hybridlab 1.0软件对STRUCTURE和NewHybrids检测杂种的准确性进行量化。还通过随机森林分类对来自[具体树种1]的两个种群和[具体树种2]的两个种群的131个样本进行形态分析。在GenAlex 6.501中通过主坐标分析（PCoA）对数据进行比较。
在所研究的所有种子林分中均观察到[具体树种1]和[具体树种2]之间的杂交，这导致后一物种中理想的造林性状得到增强。在[具体树种1]中，分子检测到的杂种中只有约16%与形态学鉴定的杂种相对应。然而，[具体树种1]的形态与一个种群中分子鉴定的杂种不一致，仅与另一个种群中3.3%的杂种一致。
这是墨西哥松树杂种优势（杂种活力）的首次报道。关于杂交和渐渗的信息对于制定未来有效的育种计划、成功建立人工林以及天然林分管理至关重要。了解自然杂交如何影响松树对气候变化的进化和适应是包括适应性造林学在内的可持续森林管理的基石。
