Volume-based selection in Pinus pinaster Aiton breeding: evaluating resistance to Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle and wood properties

Abstract

Abstract Key message Genetic parameter estimates at age 12 years for trunk volume in Pinus pinaster displayed low to moderate heritability for growth and stem form, whereas wood properties showed high heritability. No correlation was detected between resistance to the nematode Bursaphelenchus xylophilus and growth, stem form, or wood properties. However, certain families stood out, showing favorable values across all traits, including resistance to the nematode. Context The breeding program for Pinus pinaster should advance towards a second-generation breeding population based on volume, stem form, and resistance to Bursaphelenchus xylophilus, with the challenge of incorporating novel traits of importance. Aims We focused on assessing the genetic parameters of growth, stem form, wood properties, and resistance to B. xylophilus as well as exploring the relationship between these traits. Methods We evaluated 116 half-sib families at three ages (7, 12, and 17 years) in seven progeny trials established in 2005, analyzing growth, stem form, and wood traits. Resistance to B. xylophilus was assessed in 91 of the 116 half-sib families at age 2 by artificial inoculation tests under greenhouse conditions. Results Advancing the selection age to 12 years proved to be feasible for volume selection in Galician P. pinaster. All traits, including resistance to B. xylophilus, showed potential for genetic improvement. Remarkably, resistance to B. xylophilus was not correlated to any other trait. Conclusion Excluding the most susceptible families to B. xylophilus from the Galician P. pinaster breeding program would not result in a significant decrease in volume, stem form, or wood properties.

Keywords

• Maritime pine
• Pinewood nematode
• Basic density
• Modulus of elasticity
• Genetic correlations