Tall Pinus luzmariae trees with genes from P. herrerae

Christian Wehenkel; Samantha Del Rocío Mariscal-Lucero; M Socorro González-Elizondo; Víctor A Aguirre-Galindo; Matthias Fladung; Carlos A López-Sánchez

doi:10.7717/peerj.8648

Tall Pinus luzmariae trees with genes from P. herrerae

PeerJ. 2020 Feb 26:8:e8648. doi: 10.7717/peerj.8648. eCollection 2020.

Authors

Christian Wehenkel¹, Samantha Del Rocío Mariscal-Lucero^{1

2}, M Socorro González-Elizondo³, Víctor A Aguirre-Galindo¹, Matthias Fladung⁴, Carlos A López-Sánchez⁵

Affiliations

¹ Instituto de Silvicultura e Industria de la Madera, Universidad Juárez del Estado de Durango, Durango, Mexico.
² Instituto Tecnológico del Valle del Guadiana, Tecnológico Nacional de México, Durango, Mexico.
³ CIIDIR Durango, Instituto Politécnico Nacional, Durango, Mexico.
⁴ Thünen-Institute of Forest Genetics, Grosshansdorf, Germany.
⁵ Department of Organisms and Systems Biology, University of Oviedo, Polytechnic School of Mieres, Asturias, Spain.

Abstract

Context: Pinus herrerae and P. luzmariae are endemic to western Mexico, where they cover an area of more than 1 million hectares. Pinus herrerae 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.

Aims: We aimed to determine the degree of hybridization between P. herrerae and P. luzmariae in seed stands of each species located in the Sierra Madre Occidental, Durango, Mexico.

Methods: 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 P. herrerae and two populations of P. luzmariae was also conducted by Random Forest classification. The data were compared by Principal Coordinate Analysis (PCoA) in GenAlex 6.501.

Results: Hybridization between Pinus herrerae and P. luzmariae was observed in all seed stands under study and resulted in enhancement of desirable silvicultural traits in the latter species. In P. luzmariae, only about 16% molecularly detected hybrids correspond to those identified on a morphological basis. However, the morphology of P. herrerae is not consistent with the molecularly identified hybrids from one population and is only consistent with 3.3 of those from the other population.

Conclusions: 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.

Keywords: AFLP; Adaptive silviculture; Australes; Interspecific hybrids; Monitoring; NewHybrids; Random Forest; STRUCTURE; Tree breeding; Tree species.

Grants and funding

This work was supported by CONAFOR, Mexico. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.