Genetic Gain and Diversity under Different Selection Methods in a Breeding Seed Orchard of Quercus serrata

Abstract

Genetic gain and diversity were estimated in a 13- year old Quercus serrata breeding seed orchard under three selection (rouging) methods. The selections were based on individual selection, family selection, and family plus within family selection. Genetic gain was for stem volume and gene diversity was estimated by status number concept. Both estimated genetic gain and gene diversity were compared to those before selection and among selection scenarios. Estimated genetic gain for tree volume ranged from 4.0% to 9.1% for three selection methods under 50% selection intensity. Individual selection was better than family selection for retaining higher genetic gain and status number. Family plus within family selection was the best selection method, while individual selection was more efficient at the strong selection intensity. An optimal point, which maximized gain and diversity, was occurred at 50% selection intensity that would be applied for genetic thinning in the breeding seed orchard of Quercus serrata. The effect of genetic relatedness among families and possible pollen contamination on both genetic gain and gene diversity, although were not studied but their impact, are discussed. The selection method and intensity level applied should be chosen after careful consideration of the impacts on both genetic gain and diversity for seeds produced from the seed orchard.

Oaks: an evolutionary success story

“…Previous reviews of North American oaks (mainly Q. alba , Q. rubra , Q. falcata and Q. pagoda ) (Kriebel, ) and European oaks (mainly Q. petraea and Q. robur ) (Kleinschmit, ) highlighted the existence of already extremely variable phenotypes within and between progenies raised in common gardens in terms of height and diameter growth, crown form and phenology. Similar outcomes were also observed more recently in Asian species for growth (in Q. acutissima (Na et al , ) and Q. serrata (Kang et al , )). Within the context of environmental change, attention has shifted towards fitness‐related traits, such as phenology, resistance to biotic and abiotic stresses, and reproduction (Ramirez‐Valiente et al , ; Brendel et al , ).…”

Estimation of genetic gain and diversity under various genetic thinning scenarios in a breeding seed orchard ofQuercus acutissima

“…To compare ΔG among the three thinning scenarios (see below), the thinning intensities were kept constant across all genetic thinning scenarios. The three thinning scenarios used were directed and applied as (Lindgren & Matheson 1986;David et al 2003;Kang et al 2007):…”