Verryn, SDSnedden, CLEatwell, KA2009-12-072009-12-072009-06Verryn, SD, Snedden, CL and Eatwell, KA. 2009. Comparison of deterministically predicted genetic gains with those realised in a South African Eucalyptus grandis breeding program. Southern Forests, Vol.71(2), pp 141-1462070–2620http://www.ingentaconnect.com/content/nisc/sfjfs/2009/00000071/00000002;jsessionid=5ltcsag20v7h.victoriahttp://hdl.handle.net/10204/3808Copyright: National Inquiry Services Centre (NISC) 2009. This is the author's version of the work. It is posted here by permission of National Inquiry Services Centre for your personal use. Not for redistribution. The definitive version was published in journal, Southern Forests, Vol. 71(2), pp 141-146Tree breeders attempt to predict the genetic gains that are likely to be achieved through selection and breeding of new generations, using stochastic or deterministic modelling. There are many factors that may cause a discrepancy between the predicted and realised genetic gains. Often the predictions for genetic gains are based on single trait selection, whereas in reality the breeding tends to be multitrait in nature. The violation of Hardy-Weinberg conditions, assumptions regarding outcrossing and relatedness, assumptions regarding the effect of the interaction between the environment and the genotype, and numerous possible errors in the process of breeding, all could result in unexpected discrepancies between the realised and predicted genetic gains. A series of genetic gains trials containing representatives of three generations of Eucalyptus grandis selections were compared with the view to verifying the effectiveness of the E. grandis breeding program. Genetic gains of the F3 (third generation of pedigreed progeny) over the F2 generation (second generation of pedigreed progeny) were 15% for tree growth (volume). A comparison between F2 and P0 revealed an improvement of between 20% and 33% for growth. This exercise highlighted complexities of modelling the predicted genetic gains of assimilated genetic breeding trials. The predictions of genetic gains did deviate (in both directions) from those realised, although these deviations may be explained as functions of imperfect modelling. On average, however, the predicted genetic gains for tree volume over three generations was 13% between generations, whereas the average realised genetic gain in the genetic gains trial was 14%. It is therefore assumed that the E. grandis breeding population is indeed performing as expected, following classical tree breeding assumptions.enEucalyptus grandisBreeding populationGenetic gainsDeterministic modellingArticleVerryn, S., Snedden, C., & Eatwell, K. (2009). Comparison of deterministically predicted genetic gains with those realised in a South African Eucalyptus grandis breeding program. http://hdl.handle.net/10204/3808Verryn, SD, CL Snedden, and KA Eatwell "Comparison of deterministically predicted genetic gains with those realised in a South African Eucalyptus grandis breeding program." (2009) http://hdl.handle.net/10204/3808Verryn S, Snedden C, Eatwell K. Comparison of deterministically predicted genetic gains with those realised in a South African Eucalyptus grandis breeding program. 2009; http://hdl.handle.net/10204/3808.TY - Article AU - Verryn, SD AU - Snedden, CL AU - Eatwell, KA AB - Tree breeders attempt to predict the genetic gains that are likely to be achieved through selection and breeding of new generations, using stochastic or deterministic modelling. There are many factors that may cause a discrepancy between the predicted and realised genetic gains. Often the predictions for genetic gains are based on single trait selection, whereas in reality the breeding tends to be multitrait in nature. The violation of Hardy-Weinberg conditions, assumptions regarding outcrossing and relatedness, assumptions regarding the effect of the interaction between the environment and the genotype, and numerous possible errors in the process of breeding, all could result in unexpected discrepancies between the realised and predicted genetic gains. A series of genetic gains trials containing representatives of three generations of Eucalyptus grandis selections were compared with the view to verifying the effectiveness of the E. grandis breeding program. Genetic gains of the F3 (third generation of pedigreed progeny) over the F2 generation (second generation of pedigreed progeny) were 15% for tree growth (volume). A comparison between F2 and P0 revealed an improvement of between 20% and 33% for growth. This exercise highlighted complexities of modelling the predicted genetic gains of assimilated genetic breeding trials. The predictions of genetic gains did deviate (in both directions) from those realised, although these deviations may be explained as functions of imperfect modelling. On average, however, the predicted genetic gains for tree volume over three generations was 13% between generations, whereas the average realised genetic gain in the genetic gains trial was 14%. It is therefore assumed that the E. grandis breeding population is indeed performing as expected, following classical tree breeding assumptions. DA - 2009-06 DB - ResearchSpace DP - CSIR KW - Eucalyptus grandis KW - Breeding population KW - Genetic gains KW - Deterministic modelling LK - https://researchspace.csir.co.za PY - 2009 SM - 2070–2620 T1 - Comparison of deterministically predicted genetic gains with those realised in a South African Eucalyptus grandis breeding program TI - Comparison of deterministically predicted genetic gains with those realised in a South African Eucalyptus grandis breeding program UR - http://hdl.handle.net/10204/3808 ER -