Evaluating Douglas Fir's Provenances in Romania Through Multi-Trait Selection

Area of Science:

• Forest genetics and tree breeding
• Quantitative genetics
• Silviculture

Background:

• Douglas fir (Pseudotsuga menziesii) is a key timber species introduced to Europe from North America.
• Understanding provenance variation is crucial for effective tree breeding and sustainable forest management.

Purpose of the Study:

• To select the most valuable and stable Douglas fir provenances in Romania.
• To combine growth and quality traits for improved genetic resource selection.
• To assess Douglas fir adaptability in the Carpathian region.

Main Methods:

• Utilized three common garden experiments established in 1977 in Romania.
• Evaluated 61 Douglas fir provenances from diverse origins (USA, Canada, Europe).
• Applied multi-trait genotype-ideotype distance index (MGIDI) and multi-trait stability index (MTSI) to analyze diameter at breast height (DBH), total height (TH), and pruned height (PH).

Main Results:

• Significant genotype-environment interactions were detected, with optimal growth observed in Aleșd, western Romania.
• MGIDI and MTSI identified high-performing provenances from the Pacific Northwest, Europe, and Canada.
• Selection differentials for individual traits ranged from 2.8% to 10.9%, indicating substantial genetic improvement potential.

Conclusions:

• Selected Douglas fir provenances are valuable genetic resources adapted to Carpathian environmental conditions.
• Findings support the development of climate-adaptive breeding strategies for Douglas fir in Romania.
• This research contributes to sustainable forest management practices for this important timber species.