Summary A situation is described where breeding values (BVs) predicted by Best Linear Unbiased Prediction for selection criteria are used to predict an aggregate breeding objective consisting of traits that may or may not have been measured. The index weights by which the predicted BVs are multiplied are the same for all animals with the same available predicted BVs, and they depend only on the genetic variances and covariances among the selection criteria and the traits in the objective, and on the economic values of these traits. The variance of the index and expected genetic gains in both the selection criteria and the traits of the objective, however, depend on the inbreeding coefficient and the prediction error variances and covariances of the predicted BVs for each animal. When these prediction error variances and covariances are not available for all animals approximations based on assumed “standard” animals might be used to give an indication of the direction in which the population will move under selection. Zusammenfassung Wirtschaftliche Indices aus mit BLUP geschätzten Zuchtwerten Mit BLUP (Best Linear Unbiased Prediction) geschätzte Zuchtwerte (ZW) für meßbare Selektionskriterien werden zum Schätzen eines Zuchtzieles verwendet, welches sowohl gemessene als auch nicht gemessene Merkmale enthalten kann. Die Indexgewichte, mit denen die geschätzten ZW multipliziert werden, sind für alle Tiere mit den gleichen verfügbaren ZW identisch. Sie hängen nur von den genetischen Varianzen und Kovarianzen der Selektionskriterien und der Merkmale im Zuchtziel und den wirtschaftlichen Gewichten für diese Merkmale ab. Die Varianz des Indexes und die erwarteten Zuchtfortschritte in den einzelnen Indexkriterien und Merkmalen im Zuchtziel hängen dagegen vom Inzuchtkoeffizienten und den Varianzen und Kovarianzen der geschätzten ZW (prediction error variances and covariances) für jedes Tier ab. Wenn die Varianzen und Kovarianzen der geschätzten ZW nicht für jedes Tier verfügbar sind, können auf angenommenen “Standardtieren” beruhende Näherungen verwendet werden, um einen Hinweis zu erhalten, in welche Richtung sich die Population bei Selektion nach diesem Index verschieben wird.

Inbreeding coefficients were computed for 910,444 animals of the Swiss Braunvieh population. Of the animals born in 1984, 71.5% were inbred with 67.9, 3.4, and .2% having inbreeding coefficients between greater than 0 and 5%, greater than 5 to 10%, and greater than 10%, respectively. The average inbreeding coefficient was 1.14% but, for animals with both parents and at least one grandparent known, it was 1.67%. Breeding values for total milk, fat, and protein yields and for fat and protein percentages were predicted using a repeatability animal model including a regression on the inbreeding coefficient. Phenotypic performance was sizeably depressed for milk yield only (-26 kg/% of inbreeding or 2.4% of the phenotypic standard deviation). Adjusting for inbreeding increased the estimated genetic trend slightly. Inbreeding is only partially accounted for when it is ignored in the construction of the inverse of the numerator relationship matrix. This effect was investigated by comparing predicted breeding values from a model including the complete matrix with predicted breeding values from a model including a matrix constructed with inbreeding ignored. Only .8% of all predicted breeding values were affected by more than +/- 5.5 kg. The maximum difference observed was 55.3 kg. The observed average absolute differences between the breeding values of offspring predicted with the two models increased with inbreeding of parents.

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Lepidopteran insects are major pests of agricultural crops, and mated female moths exploit plant volatiles to locate suitable hosts for oviposition. We investigated the heritability of odor-guided host location behavior and fecundity in the cosmopolitan oriental fruit moth Grapholita (Cydia) molesta, an oligophagous herbivore that attacks fruit trees. We used a full-sib/half-sib approach to estimate the heritability and the genetic correlation between these two traits. Results document a considerable genetic basis for olfactory attraction of females (h ( 2 ) = 0.37 ± 0.17) and their fecundity (h ( 2 ) = 0.32 ± 0.13), as well as a genetic trade-off between female attraction and fecundity (r ( g ) = -0.85 ± 0.21). These estimations were empirically corroborated by comparing two strains maintained in the laboratory for different numbers of generations. The long-term reared strain lost its olfactory discrimination ability but achieved significantly higher fecundity compared with the short-term reared strain. Our results highlight that genetic studies are relevant for understanding the evolution of odor-guided behavior in herbivore insects and for judging the promise of pest management strategies involving behavioral manipulation with plant volatiles.

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