Assortative mating and artificial selection

Baker, Richard J.

doi:10.1038/hdy.1973.78

Cited by 23 publications

(15 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this study, the redistribution of test resources among families by varying their sizes under fixed total test resources magnified the effect of PAM, which by itself provides a large enhancement of V A(BP) , particularly under low-selection-intensity scenarios (Baker 1973;De Lange 1974;Jorjani 1995;. The enhancement of V A(BP) observed in this study exceeds the magnitude reported earlier under unbalanced mating schemes Lstibů rek et al 2004).…”

Section: Resultscontrasting

confidence: 49%

Positive Assortative Mating With Family Size as a Function of Predicted Parental Breeding Values

et al. 2005

View full text Add to dashboard Cite

While other investigations have described benefits of positive assortative mating (PAM) for forest tree breeding, the allocation of resources among mates in these studies was either equal or varied, using schemes corresponding only to parental rank (i.e., more resources invested in higher-ranking parents). In this simulation study, family sizes were proportional to predicted midparent BLUP values. The distribution of midparent BLUP values was standardized by a constant, which was varied to study the range of distributions of family size. Redistributing progenies from lower-to higher-ranking families to a point where an equal number of progenies were still selected out of each family to the next generation caused minimal change in group coancestry and inbreeding in the breeding population (BP), while the additive genetic response and variance in the BP were both greatly enhanced. This generated additional genetic gains for forest plantations by selecting more superior genotypes from the BP (compared to PAM with equal family sizes) for production of improved regeneration materials. These conclusions were verified for a range of heritability under a polygenic model and under a mixed-inheritance model with a QTL contributing to the trait variation. E ARLIER studies by computer simulation have demonstrated that positive assortative mating (PAM) applied in a long-term forest tree breeding program has the potential to generate extra genetic improvement in forest plantations (e.g., dissertations by Mahalovich 1990; Rosvall 1999). This is due to the enhancement of the additive genetic response and variance in the breeding population (BP), enabling the selection of more extreme genotypes from the BP. These genotypes can be established in orchards to produce seeds for production of reforestation nursery stock or alternatively can be vegetatively propagated and directly planted as clones. When both genetic gain and diversity are considered in a single selection criterion, PAM does not much alter the effective population size compared with that achieved under random mating, but increases the average inbreeding in the BP as a consequence of mating among more related individuals .Ideally, the contribution of individuals in the BP to the next generation should correlate with their breeding values (Lindgren 1986). Various weighting schemes have been proposed to assign mating frequencies to individuals in the BP. These are built on different assumptions about the distribution of breeding values and the function used to assign the corresponding mating frequencies Kang 1989;Wei and Lindgren 1995). Two approaches for controlling parental contributions during PAM were investigated by , using a stochastic model of a forest-tree breeding program. In the first approach, balanced mating (each individual involved in an equal number of combinations) was followed by unbalanced selection (more progenies selected from higher-ranking families and fewer from lower-ranking families). In the second, unbalanced mating (individuals of high...

show abstract