Genetic variation and early selection in Larix decidua Mill. from progeny test in Romania

Abstract

High genetic variation and determinism for quantitative traits ofLarix deciduaMill. were found in a progeny test established at its south-eastern limit of distribution area. The top range families are from both native populations and artificial stands of unknown origin. Recurrent selection at the nursery stage based on total height can reduce the generation time and increase the genetic gain. Despite the economic and ecological importance of Larix decidua in Europe, little information is available regarding its genetic variation and genetic parameters, particularly in the south-eastern part of its distribution area. The objectives of this study were to investigate genetic variation, to estimate genetic parameters and to predict genetic gain in three alternative selection strategies for quantitative traits of L. decidua in a progeny experiment at the nursery stage. Genetic variation of growth, branch traits and bud flushing were assessed in an open-pollinated progenies from 56 plus trees of L. decidua. Plus trees were selected from two natural populations (native to the Romanian Carpathians) and four artificial stands of unknown origin (most likely from the Austrian Alps). Analysis of variance was performed at three levels: provenance region, family and within family. The variance components, coefficients of heritability, genetic and phenotypic correlations, and genetic gain were also determined. Large genetic variation in quantitative traits was found among L. decidua open-pollination families. Results highlight high genetic control for growth traits and bud flushing and support the premise that the strategy based on recurrent selection will bring the greatest genetic gain in the next breeding generation. Results complete the knowledge concerning genetic parameters of some traits important for L. decidua breeding programmes in Europe. Further analysis is necessary in order to determine the origin of the genitors involved in the next breeding cycle, given that the best families come from both natural populations and artificial stands, which are very most likely from the Tyrolean Alps.