Ávila-Flores Israel Jaime, Hernández-Díaz José Ciro, González-Elizondo Maria Socorro, Prieto-Ruíz José Ángel, Wehenkel Christian
Doctorado Institucional en Ciencias Agropecuarias y Forestales, Universidad Juárez del Estado de Durango, Apdo, Postal 741, Zona Centro, Durango, Durango, México, C.P., 34000.
Instituto de Silvicultura e Industria de la Madera, Universidad Juárez del Estado de Durango, Apdo, Postal 741, Zona Centro, Durango, Durango, México, C.P., 34000.
PLoS One. 2016 Apr 11;11(4):e0152651. doi: 10.1371/journal.pone.0152651. eCollection 2016.
Hybridization is an important evolutionary force, because interspecific gene transfer can introduce more new genetic material than is directly generated by mutations. Pinus engelmannii Carr. is one of the nine most common pine species in the pine-oak forest ecoregion in the state of Durango, Mexico. This species is widely harvested for lumber and is also used in reforestation programmes. Interspecific hybrids between P.engelmannii and Pinus arizonica Engelm. have been detected by morphological analysis. The presence of hybrids in P. engelmannii seed stands may affect seed quality and reforestation success. Therefore, the goals of this research were to identify introgressive hybridization between P. engelmannii and other pine species in eight seed stands of this species in Durango, Mexico, and to examine how hybrid proportion is related to mean genetic dissimilarity between trees in these stands, using Amplified Fragment Length Polymorphism (AFLP) markers and morphological traits. Differences in the average current annual increment of putative hybrids and pure trees were also tested for statistical significance. Morphological and genetic analyses of 280 adult trees were carried out. Putative hybrids were found in all the seed stands studied. The hybrids did not differ from the pure trees in vigour or robustness. All stands with putative P. engelmannii hybrids detected by both AFLPs and morphological traits showed the highest average values of the Tanimoto distance, which indicates: i) more heterogeneous genetic material, ii) higher genetic variation and therefore iii) the higher evolutionary potential of these stands, and iv) that the morphological differentiation (hybrid/not hybrid) is strongly associated with the Tanimoto distance per stand. We conclude that natural pairwise hybrids are very common in the studied stands. Both morphological and molecular approaches are necessary to confirm the genetic identity of forest reproductive material.
杂交是一种重要的进化力量，因为种间基因转移能够引入比突变直接产生的更多新遗传物质。恩氏云杉（Pinus engelmannii Carr.）是墨西哥杜兰戈州松栎林生态区九种最常见的松树物种之一。该物种因木材而被广泛采伐，也用于造林计划。通过形态学分析已检测到恩氏云杉与亚利桑那松（Pinus arizonica Engelm.）之间的种间杂种。恩氏云杉种子林分中杂种的存在可能会影响种子质量和造林成功率。因此，本研究的目标是在墨西哥杜兰戈州该物种的八个种子林分中，鉴定恩氏云杉与其他松树物种之间的渐渗杂交，并使用扩增片段长度多态性（AFLP）标记和形态特征来研究杂种比例与这些林分中树木之间平均遗传差异的关系。还对推定杂种和纯树的平均年生长量差异进行了统计学显著性检验。对280株成年树木进行了形态学和遗传学分析。在所研究的所有种子林分中均发现了推定杂种。杂种在活力或健壮程度上与纯树没有差异。通过AFLP和形态特征检测到推定恩氏云杉杂种的所有林分，其塔尼莫托距离（Tanimoto distance）平均值最高，这表明：i）遗传物质更具异质性，ii）遗传变异更高，因此iii）这些林分具有更高的进化潜力，以及iv）形态分化（杂种/非杂种）与每个林分的塔尼莫托距离密切相关。我们得出结论，在所研究的林分中自然成对杂种非常常见。形态学和分子方法对于确认森林繁殖材料的遗传身份都是必要的。
