Expansion of the minimum-inbreeding seed orchard design to operational scale (original) (raw)
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Current Advances in Seed Orchard Layouts: Two Case Studies in Conifers
Currently, there has been an increasing demand on seed orchard designs with respect to mitigating inbreeding in advanced generations or facing severe mortality at sites. Optimum Neighborhood Algorithm design (ONA) excels in solving these issues, as shown in two case studies. The first demonstrates the application of the ONA for populating empty positions in an existing orchard. Following this concept, the ONA can be used for upgrading existing orchards, where only high-value parents are retained and new parents are introduced, thus avoiding the genetic penalty associated with the establishment of new-generation seed orchards. The second illustrates benefits of combining the ONA with the Minimum Inbreeding (MI) seed orchard design. Utilizing the MI, distances among clonal rows of selected clones were maximized on the orchard grid while the remaining single-tree positions were populated by ONA.
Randomized, replicated, staggered clonal-row (R2SCR) seed orchard design
Tree Genetics & Genomes, 2014
Spatial randomization of clones across a seed orchard's grid is commonly applied to promote crossfertilization and minimize selfing. The high selection differential attained from advanced-generation breeding programs sets high premier on the genetic gain and diversity delivery from seed orchards, thus clonal allocation is important and even more challenging when clones share common ancestry. Evidences of low selfing in many conifers' seed orchards, as a result of their high genetic load, inbreeding depression, and polyembryony are abundant and call for orchards' design reevaluation, specifically when randomization is associated with added managerial burden. Clonal-rows represent a viable option for simplifying orchards management; however, they are often associated with elevated correlated matings between adjacent clones. Here, we propose a modified clonal-row design that replicates, staggers, and randomizes the rows, thus doubling the number of adjacent clones and providing different set of neighboring clones at each replication, thus allowing accommodating related parents more readily than any singletree arrangement. We present a novel algorithm packaged in user-friendly software for executing various seed orchards' designs. The developed program is interactive and suitable for any orchard size and configuration, accommodates any number of clones that are allocated to rows with variable length (ranging from a single tree to any even number) and pre-set separation zone between ramets of the same clone. The program offers three deployment modes (equal, linear, and custom) each with multiple layouts determined by the number of iterations requested. The resulting layouts are ranked based on four criteria including: (1) the number of empty positions, (2) deviation between expected and observed clone size, (3) minimum inbreeding, and (4) a neighborhood index that expresses the efficiency of clonal distribution.
Tree Genetics & Genomes, 2009
Genetic gain and diversity of seed orchards' crops are determined by the number of parents, their breeding values and relatedness, within-orchard pollination efficiency, and level of pollen contamination. These parameters can be manipulated at establishment by varying clonal representation (e.g., linear deployment), during orchard development by genetic thinning, or by selective harvesting. Since clonal fecundities are known to vary both within and among years, then each seed crop has a unique genetic composition and, therefore, crops should be treated on a yearly basis. Here we present an optimization protocol that maximizes crop's genetic gain at any desired genetic diversity through the selection of a subset of the crop that meets both parameters. The genetic gain is maximized within the biological limit set by each clone's seed-cone production and effective population size is used as a proxy to genetic diversity whereby any relationship among clones is considered. The optimization was illustrated using 3 years' reproductive output data from a first-generation western larch seed orchard and was tested under various scenarios including actual male and female reproductive output and male reproductive output assumed to be either equal to that of female or a function of clonal representation. Furthermore, various levels of co-ancestry were assigned to the orchard's clones in supplementary simulations. Following the optimization, all solutions were effective in creating custom seedlots with different gain and diversity levels and provided the means to estimate the genetic properties of composite seedlots encompassing the remaining "unused" seed from a number of years.
Tree Genetics & Genomes, 2006
Self-pollen seldom results in vital genotypes and can thus be regarded as unimportant. Large-sized clones (clones with many ramets) are more exposed to self-pollen and spread more self-pollen and thus contribute relatively less than small-sized clones. The size of clones required to maximize genetic gain at given diversity, considering that only outcrossing contributes to successful gametes, was derived for tested clones intended to establish a Norway spruce (Picea abies) seed orchard. The derived optimal deployment was compared with linear deployment according to Lindgren and Matheson (Silvae Genet 35:173-177, 1986), where the size of a clone is deployed proportional to its breeding value. The study covered a range of effective numbers between 5 and 50. The results suggest that linear deployment is a good approximation to optimal deployment when only outcrossing is considered. The difference between the two strategies is decreased by increasing clone number and is negligible except at low effective numbers.
A New Generation of Clonal Seed Orchards of Wild Cherry. Selection of Clones and Spatial Design
2015
Forest policy in Flanders (Belgium) strongly promotes the use of indigenous hardwoods, among which wild cherry (Prunus avium L.), for re- and afforestation and for stand conversion,. This line of policy generates a strong demand for high quality forest reproductive material, which cannot be met by the currently available basic material. The selection and breeding programme attempts to remedy the discrepancy between supply and demand by creation of a new generation of clonal seed orchards characterised by (i) a high yield and (ii) a high genetic quality and diversity of the offspring. This goal was achieved by selection of 52 genotypes based on half-sib progeny trials. Yield and genetic quality of the offspring was enhanced to a further extend by adjusting the spatial design of the seed orchard to the phenologically and gametophyticaly cross-compatibility of the selected genotypes. Background pollination is reduced to a minimum by establishment of the seed orchard at a minimum distan...
Clonal-row versus random seed orchard designs: interior spruce mating system evaluation
Canadian Journal of Forest Research, 2007
Mating system pattern (selfing or outcrossing and correlated matings levels) comparisons between two interior spruce seed orchard designs (clonal-row and random) managed under intensive crown and pollen management were conducted. Crown manipulation consisted of tree topping and branch pruning, while pollen management involved multiple supplemental mass-pollination applications during peak seed-cone reproductive receptivity and pollen agitation using helicopters. Significant differences between orchards' multilocus outcrossing rate estimates were observed, and both estimates significantly departed from complete outcrossing (t = 1.0). Clonal arrangements in the clonal-row design permitted higher chances for selfing (t = 0.948) in comparison with those of the random design (t = 0.989). Intensive pollen management, while effective, still produced a minor component of selfing. Both orchard designs produced similar individual tree's outcrossing rate trends with the majority showing high outcrossing, while few individuals showed high selfing propensity. Estimates of correlated mating varied substantially between the two seed orchard designs with 9.3% and 4.3% for the clonal-row and random seed orchards, respectively. While small but significant differences in the genetic quality of the seed crops were observed between the two orchard designs, the establishment of clonal-row seed orchards should be given serious considerations specifically under committed pollen and crown management. The ease of crop and orchard management in the clonal-row design outweighs the observed differences in the seed crop genetic quality. A slight modification to the clonal-row design is proposed and is expected to reduce the observed minor genetic quality differences between the two orchard designs.
Optimized Planning of Assortment Production in Forest Stands
FLORESTA, 2019
This study aimed to evaluated two optimized planning strategies and analyze their performance in timber production. Data were obtained in Pinus spp. stands from a forestry company with unbalanced planted area over time. Maximization models of forest production (1) and net present value (2) were formulated and two minimization objective functions of the production deviation (3) and minimum and maximum production oscillation (4) were tested as alternatives to the traditional models. The highest thinning and clearcutting average areas were obtained in strategy 1. Strategies 1 and 2 resulted in the greatest variability of forestry operations. All strategies resulted in the highest timber production for sawn and special sawn wood and the lowest for veneer, while the pulpwood volume was almost constant. Strategies 1 and 2 provided the highest average timber volume and the greatest variability in the production, while strategies 3 and 4 were more efficient, since they supplied the industri...