Breeding Cycler


Long term breeding can be described as population improvement over repeated cycles of mating, testing and selection. Breeding cycler is a tool for evaluation over one single cycle, which also can be used for optimisation. Multi-generation breeding is multiple repeats of such breeding cycles.

Grandparent balanced selection, which allows variable contributions from parents constrained by the parental contribution, is a special variant of Breeding Cycler, which has own workbooks. Two sheets are available, the first we call Mira and is associated to the CJFR paper below. The more advanced Wilhelm is is associated to the Annals of Forest Science paper! There is also an EXCEL 2007 version, I guess the best way to get it is to choose the "save target as" option . Grandparent balanced selection is also available at www.mi.lt/research.htm  (at bottom of page), the idea is that that web will soon take over the development of the "breeding cycler web", but still this page is later updated.

A best breeding strategy considering genetic gain, gene diversity, cost, time and testing strategy can be found by experimenting with the deterministic simulator BREEDINGCYCLE2004.XLS. A slightly modified version is  BREEDINGCYCLE2006.XLS.

This is a deterministic simulator aiming to compare strategies for testing and selection to the next generation of the breeding population in a long term breeding program. The simulator can handle (1) phenotypic selection, (2) clonal test, and (3) progeny test. Juvenile-mature correlation is one key component, the simulator offer you alternatives for that. The simulator deals only with within family selection and a family is considered a population (this is not quite correct for the grandparent sheets). The testing can be arranged in two stages with a pre-selection preceding the final selection. The simulator compares simultaneously gain, gene diversity, cost, time and testing strategy. It is possible to search for a strategy which maximises annual group merit progress under the constraint of an available annual budget.

 
The studies have been presented at seminars slide shows 2004, 2008 and 2009. The simulator is a cooperative project between Dag Lindgren and Darius Danusevicius.

 Danusevicius D & Lindgren D 2002. Efficiency of Selection Based on Phenotype, Clone and Progeny Testing in Long-term Breeding. Silvae Genetica 51:19-26
Danusevicius D & Lindgren D 2002. Two-stage selection strategies in tree breeding considering gain, diversity, time and cost. Forest Genetics. 9:145-157.
Danusevičius, D. and Lindgren, D. 2003. Clonal testing may be the best approach to long-term breeding of Eucalyptus. In: Eucalyptus Plantations – Research, Management and Development, R.-P. Wei and D. Xu (eds), World Scientific, Singapore, 192-210.
Danusevičius, D. and Lindgren, D. 2004. Progeny testing preceded by phenotypic pre-selection - timing considerations. Silvae Genetica 53: 20-26.
Danusevičius, D. and Lindgren, D. 2005. Optimisation of breeding population size for long-term breeding. Scandinavian Journal Forest Research (20) 1: 18-25.
Li H, Lindgren D, Danusevicius D, Cui J 2005.  Theoretical analyses of testing efficiency in long-term breeding of poplar. Journal of Forestry Research 16:275-280.
Danusevičius D & Lindgren D. 2006. Optimization of long term breeding strategies for cyclic within family selection. IUFRO 2.04.02 Breeding theory and progeny testing Newsletters 1:26. (Summary of results 2002-2005)

Lindgren D, Danusevičius D & Rosvall O 2008. Balanced forest tree improvement can be enhanced by selecting among many parents but keeping balance among grandparents. Canadian Journal of Forest Research  38(11): 2797–2803.
Danusevicius D & Lindgren D 2010. Efficiency of breeding strategy where grandparents - but not parents - contribute equally to the breeding population. Annals of Forest Science. In press.

The values of some of the variables used as entries may change over time, but the change is small and the optimum will change only slowly, in the few cycles forest tree breeders deal with this change can be neglected.  

Acknowledgements: Later developments (since 2007) were supported by The Swedish Association for Forest Tree Breeding.

This webpage  was last edited 2009-12-15 by Dag Lindgren