Genetic basis of wavy grain in sycamore maple (Acer pseudoplatanus L.): Indications for a locus with dominant effect

Abstract

Wavy grain is a rare and highly valued wood characteristic that significantly increases the market price of sycamore maple (Acer pseudoplatanus L.) timber. However, the genetic basis of this striking trait has remained unclear. Here, the inheritance of this trait was investigated using a unique two-generation pedigree including progeny of 21 parental sycamore maple clones, several of which exhibit wavy grain. Parentage analysis based on 12 microsatellite markers enabled the reliable assignment of most of the 599 offspring to defined parental combinations in this tetraploid species. Wood structure was assessed macroscopically in 113 felled trees from a 35-year-old field trial and classified as either wavy or straight grain. The observed segregation patterns were consistent with a dominant mode of inheritance: 71% of offspring with at least one wavy-grained parent developed wavy grain, whereas none of the offspring from two straight-grained parents exhibited the trait. The occurrence of wavy grain among offspring of wavy-grained fathers and straight-grained mothers suggests genetic inheritance through the nuclear genome. Taken together, the results provide first indications for a nuclear genetic contribution to the inheritance of wavy grain in sycamore maple. Due to the limited sample size and the tetraploid genome structure, more complex inheritance patterns cannot be completely excluded. Nevertheless, these findings offer a basis for future studies aimed at elucidating the underlying mechanisms of this rare wood characteristic and may support breeding and conservation strategies.