Posted 02 Sept 11
Milestone in Bee Breeding
A Total Breeding Value simplifies the Selection Decision
Professor Dr Kaspar Bienefeld and Dr Klaus Erhardt, Länderinstitut für Bienenkunde, Hohen Neuendorf.
E -Mail –Kaspar Bienefeld
Translated from the ADIZ/db/IF, 1/2011
by A.E. McArthur MIL
The Breeding Value Assessment for honey yield, gentleness, swarm propensity and calmness on the comb, which the Institute for Bee Research in Hohen Neuendorf has been working on since 1994 was enlarged by the inclusion of a Varroa Index a few years ago. This Varroa Breeding Index evaluates the brood hygiene (removal behaviour/needle test) and the Varroa infestation level development (estimated by the ratio of mite drop at the willow bloom period and the number of phoretic mites in a bee sample at the start of July). By so doing, two breeding values were able to be combined, thus making the breeding decision process easier for the beekeeper. The weighting factors for this Varroa Index were determined on the basis of survivability tests, which were carried out on selected untreated colonies. There still remain however 5 individual breeding values, which require to be considered simultaneously as a basis for the selection of suitable breeding colonies. For this reason from mid February 2011 onward a multi- trait, Total Breeding Value will also be offered to breeders and purchasers of queens at the internet site www.beebreed.eu.
What is a Total Breeding Value?
In a Total Breeding Value, all of the individual values corresponding to their breeding and economic significance will be combined in one number. In this, the heritability of all of the individual characteristics, the genetic relationships between them and the different significance of the individual characteristics for the breeder must be considered. The very complex calculations and new computations relative to hereditability and the genetic relationships between the characteristics are now able to be closed. The possible different significance of the qualities for the individual breeder is of course not known to us.
We recommend on the basis of the great significance of Varroa tolerance and of the up till now already very high level relative to honey yield and gentleness, that the weighting for Varroa tolerance in the Total Breeding Value be set high (40%). Discussions with the top breeders of the associations and Varroa Tolerance Working Group on this matter are still necessary and have been planned.
The very “Varroa Tolerance” – weighted, Total Breeder Value shall initially be listed as the Standard Total Breeder Value along with the Individual Breeding Values in www.beebreed.eu .
Self Weighting Possibility
Should every breeder from 2011 onward decide to use this Total Breeding Value facility when making the selection for their breeding colonies, then a significant forward step in breeding relative to Varroa tolerance can be expected. The present target of annual breeding progress for honey and gentleness will then of course be reduced. For that reason the databank, offers the possibility, to the breeders and purchaser of queens, to choose a completely personal weighting of preference for the set of selection criteria.
If one, for example in the future, constantly selects the weighting of 100% for honey yield and as a consequence a weighting for the other characteristic of 0%, then a clear selection success for honey yield would be expected, while the other characteristics will not alter, or even deteriorate. This depends on the genetic relationship between the characteristics.
The Basic Data and Calculations
In order to consider the inter-relationships between the individual genetic parameters as well as the environment and the genetically conditioned influences of the queen and her worker bees for every characteristic a Total Model based on the BLUP animal model is required.
BLUP (Best Linear Unbiased Prediction) is an established procedure in animal breeding for predicting the genetic value of an animal. The Breeding Value Estimation for the honey bee embraces the total actual performance of some 125,000 colonies recorded in the Carnica Data bank. However, breeding values for the ligustica and mellifera races are also available.
An equalisation-system has been created consisting of more than 3 million equations, which have to be solved simultaneously. This is why it is not possible to immediately calculate later refinements in the individual blocks of data, e.g corrected parentages, but which will only be effective in the next series of Breeding Value Estimation calculations. At the same time this simultaneous calculation also allows Individual Breeding Values and the Total Breeding Value to be calculated, even although not every characteristic in the performance data had been included. These Breeding Values are thus estimated from the performances of all of the related colonies. Note must be taken, that all the Individual Breeding Values are published as Relative Breeding Values. Queens with a Breeding Value of 100% correspond exactly to the average of all of the Breeding Values from the previous five years. In order to achieve comparability of Breeding Values, the scatter within a characteristic is normalised using a Standard Deviation. These procedures are also preserved with the new Total Breeding Values. The Total Breeding Value is a milestone in the breeding of honey bees. It will ease the burden of selection and assist in the development of a healthy and efficient honey bee population.
This work was funded by the Federal Ministry of Food, agriculture and Consumer Protection (BMELV), Federal Institute for Agriculture and Food (BLE), Project No. 2808UM004.