Financial feasibility of marker-aided selection in Douglas-fir

Abstract

Abstract:The land area required for a marker-aided selection (MAS) program to break-even (i.e., have equal costs and benefits) was estimated using computer simulation for coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Pacific Northwestern United States. We compared the selection efficiency obtained when using an index that included the phenotype and marker score with that obtained using only the phenotype. It was assumed that MAS was restricted to within-family selection, that the rotation age was 50 years, and that growth rate (h 2 = 0.25), tree form (h 2 = 0.25), and (or) wood density (h 2 = 0.45) were the objects of improvement. Several population quantitative trait loci (QTL) models, selection population sizes, and interest rates were considered. When large selection population sizes were employed (500 trees per family) MAS gave considerable increases in efficiency of within-family selection; however, results showed that the combination of small selection population sizes (100 trees per family) and many QTL of moderate effect could lead to losses in gain from MAS compared with phenotypic selection. For many reasonable selection scenarios and the simplified assumptions in our model, the land base required for breeding programs to breakeven is smaller or near to the limit of those in place under operational breeding programs in the region. Considerably more research is needed to reasonably predict whether MAS would be cost-effective in practice. However, before some of the basic research needed to implement MAS can be done, organizations need to establish large blocks of full-sib families to allow for QTL identification.Résumé : Les auteurs ont estimé la superficie en plantations nécessaire pour équilibrer les coûts et les bénéfices associés à un programme de sélection assistée par marqueurs (SAM). L'étude a été réalisée à l'aide de simulations informatiques pour le Douglas vert de la côte (Pseudotsuga menziesii (Mirb.) Franco), dans la région du pacifique nord-ouest, aux États-Unis. Deux méthodes de sélection ont été comparées, l'une basée sur le phénotype et la seconde basée simultanément sur le phénotype et la valeur du marqueur. Les effets de la SAM ont été évalués dans un cadre de sélection intra-familiale, en assumant un âge de révolution de 50 ans. Les caractères d'amélioration suivants ont été étudiés : le rythme de croissance (h 2 = 0,25), la forme de l'arbre (h 2 = 0,25), et/ou la densité du bois (h 2 = 0,45). Les auteurs ont considéré plusieurs modèles de population au niveau des loci contrôlant les caractères quantitatifs (QTL), ainsi que plusieurs tailles de population de sélection et plusieurs taux d'intérêt. Lorsque de grandes populations de sélection étaient considérées (500 arbres par famille), la SAM entraînait une sélection intra-familiale considérablement plus efficace. Cependant, les résultats ont démontré que la SAM pouvait entraîner une diminution du gain comparativement à la sélec-tion phénotypique, lorsqu'on était en présence de petites populations de sélection (100 ...

Breeding Douglas‐Fir

“…Pedigree-based QTL studies reveal much about the genetic architecture of growth and adaptation, and provide a foundation for markeraided-selection (MAS), which seems to be economically feasible in Douglas-fir (Johnson et al 2000;Wu et al 2000). Nonetheless, MAS will be challenging because of the polygenic control of important quantitative traits in forest trees ) and substantial linkage disequilibrium (Strauss et al 1992).…”

QTL associations for density and diameter in Pinus radiata and the potential for marker-aided selection

“…Johnson et al (2000) evaluated the financial gains from MAS, including detection costs, for Douglas fir in the Pacific Northwest. Their study indicated that relatively large areas would need to be planted with MAS-improved germplasm to justify the initial investment.…”

Genetic maps for Pinus elliottii var. elliottii and P. caribaea var. hondurensis using AFLP and microsatellite markers

“…A shorter rotation and improved juvenile wood properties are viewed as key breeding objectives for the continued market success of hybrid pine products (Haines 2000). The breeding and deployment systems used with the hybrid pine, including its amenability to vegetative propagation, relatively short rotation age and a single breeding zone suggest that MAS will be more viable than for many temperate conifers (Johnson et al 2000).…”