Apidologie

[B+.]

Interesting article from Apidologie on heritability and genetic correlation of traits using Austrian data DOI: 10.1007/s13592-016-0427-9 (http://link.springer.com/article/10.1007/s13592-016-0427-9)

 

[Truble]

Seems to suggest one should select for only trait at a time rather than use the multi-trait selection as many breeders use today.
Assuming I've interpreted it correctly.

 

[B+.]

Seems to suggest one should select for only trait at a time rather than use the multi-trait selection as many breeders use today.
Assuming I've interpreted it correctly.

It isn't recommending that you only select for one trait although it is obvious that you can make more progress per generation when only selecting for a single trait.
The interesting thing that I take from this is the evolution of the model as described in Brascamp & Bilma (2014) and its application to a larger dataset in this paper than previously used. Clearly, the more data you have, the less error.

 

[B+.]

Seems to suggest one should select for only trait at a time

My apologies. The final paragraph does indeed recommend a single trait model be adopted

"Based on our results, we do not recommend to implement a multi-trait animal model, because the required genetic correlations were estimated with very high standard errors. With such inaccurate estimates of genetic correlations, the addition of observations on other traits may actually be detrimental for the estimation of breeding values (Sales and Hill 1976). On the basis of these analyses, the single-trait animal models used here are considered suitable to estimate breeding values for honey bee colonies in populations belonging to controlled breeding programmes."

 

[Fusion_power]

It does not attempt to correct for inbreeding effects, especially as related to the sex-locus. In other words, a queens poor performance could have been due to mating with a large number of drones containing duplicated sex alleles and therefore producing a large proportion of diploid drones.

This study also suggests that multiple parallel breeding programs each focused on a single trait will give more long term gain than a single program selecting for multiple traits. One program should focus on gentleness and calmness because the two are highly correlated, one program should focus on increased honey production, etc.

What Brother Adam did by crossing multiple races of bees could be achieved by a parallel breeding program with much higher potential benefit.

This study also suggests that breeding for mite tolerance should be pursued in a line that is only bred for mite tolerance. Once mite tolerance is stable and predictable, then add selection for another desired trait by crossing with a parallel line that was developed with that focus.

 

[bpmurray]

My bees started off from three different mated queens, and their offspring will have mated with drones from the local DCA's which are populated by drones from at least three different apiaries. I would expect that this is rather typical - is inbreeding really an issue, i.e. has it been measured, or is it something that people just have a gut feeling about?

 

[B+.]

It does not attempt to correct for inbreeding effects, especially as related to the sex-locus. In other words, a queens poor performance could have been due to mating with a large number of drones containing duplicated sex alleles and therefore producing a large proportion of diploid drones.

I don't know for certain how things are done in Austria but I don't believe inbreeding is an issue. It has been common practice to use island mating stations stocked with many daughters of a single tested queen which comes from a long line of tested queens. From what I have seen of the pedigrees, inbreeding is never an issue.

I have emailed Pim for clarification.

 

[B+.]

This study also suggests that breeding for mite tolerance should be pursued in a line that is only bred for mite tolerance. Once mite tolerance is stable and predictable, then add selection for another desired trait by crossing with a parallel line that was developed with that focus.

I must have missed this. I didn't notice anything about mite tolerance

In any case, you will always come to the point where you are crossing lines that exhibit high performance for a given trait. In other words, you are dealing with a portfolio of traits. There is no escaping it.

 

[B+.]

I have emailed Pim for clarification.

Prof Brascamps reply:

In animal breeding there are two ways to estimate breeding values with animal model. They have in common that the statical analysis includes the same 'fixed' effects like testing place, and an animal effect (in our case two animal effects, worker and queen) accompanied by the relationshipsmatrix. The first way is called 'single trait' which means that breeding values are estimated separately for each trait. In case of 'multitrait' breeding values are estimated for all traits simultaneously, in one joint analysis. In the latter case additionally genetic correlations are to be entered into the analysis. In this latter case the level of one trait affects the estimated breeding of another. You see that in Beebreed for example in the case that two queens in a sister group do not get the same breeding value although they have the same observation (trait value). My idea is that the mutual effects of traits on each others estimated breeding values is very imprecise and erratic when genetic correlations are estimated very inaccurately as in the Austrian data. Sales and Hill show that addition of other trait information does not increase the accuracy with which the breeding value of a trait is estimated, and even can diminish it. I have no information about accuracy of the estimated genetic correlations in Beebreed. The amount of data is very much larger in Beebreed than in Austrian data so perhaps my argument doesn't hold for Beebreed.

On the other hand, theoretically the weighing of breeding values for different traits for their relative importance to get an aggregate breeding value is correct when individual breeding values are estimated multitrait, but not when estimated single trait. It is -translated from a Dutch proverb- like being bitten by the dog or the cat.

I hope this clarifies my point.

 

[Fusion_power]

There was noting in the article about mite tolerance, that was an extrapolation from the statement that single trait selection is likely to give more gain.

The "trait" of mite tolerance appears to be based on many small additive effect genes. My bees express VSH, allogrooming, and mite mauling and may have others that I don't know about. It would be interesting to see a good analysis of mite tolerant lines similar to this article.

Agree that eventually lines would have to be crossed and then selection carried out for the combined traits.

Is inbreeding really an issue?

Under normal conditions, no, but when an isolated mating station is involved, there is a lot of potential for duplication at the sex allele. If the parents are selected appropriately, this won't normally be an issue. On the other hand, a typical queen produces between 3 and 5 percent diploid drone eggs. Double that through poorly controlled mating and a queen might produce 10% diploid drone eggs which has very high potential to impact other performance traits such as honey production.

 

[B+.]

My bees express VSH, allogrooming, and mite mauling and may have others that I don't know about. It would be interesting to see a good analysis of mite tolerant lines similar to this article.

No disrespect intended but I think you would need a lot more control over your pedigree to even begin to perform this sort of analysis on your bees FP

 

[Truble]

Sounds like mult-trait or single trait slection doesn't matter too much in the long term. It may be quicker, bee generation times, to achieve excellence in a single trait, say honey collection but end up with bees that also have undesirable traits. I presume that the breeder would then cross to selected lines to eliminate the undesirable whilst retaining all the desirable ones (AKA Br. Adam) which would add even further time to the project.
Which method is "best" or "quickest" to achieve a bee with all the desirable characters,time wise, I don't think has ever been done.
My own thoughts are that as long as there are breeders who are able to select for these desirable characteristics and produce excellent queens for sale then I'm quite happy to purchase them. As a small scale amateur it's impractical for me to enter into a breeding program on this scale and why bother when someone else is already doing a better job than I could ever do.

 

[B+.]

My own thoughts are that as long as there are breeders who are able to select for these desirable characteristics and produce excellent queens for sale then I'm quite happy to purchase them. As a small scale amateur it's impractical for me to enter into a breeding program on this scale and why bother when someone else is already doing a better job than I could ever do.

Brother Adam crossed different races so this is different to crossing high performing lines within a race.
Anyone with the commitment to test a group of sister queens can participate in the programme. I will test 3 different family groups of Celle line, 1 group of NL-line and a number of Queens (yet to be decided) from the Arista VSH line next year. I urge others to join.

 

[B+.]

Under normal conditions, no, but when an isolated mating station is involved, there is a lot of potential for duplication at the sex allele. If the parents are selected appropriately, this won't normally be an issue. On the other hand, a typical queen produces between 3 and 5 percent diploid drone eggs. Double that through poorly controlled mating and a queen might produce 10% diploid drone eggs which has very high potential to impact other performance traits such as honey production.

See post #7
In fact, mating stations are well controlled (see http://coloss.org/beebook/I/queen-rearing/2/2/startpage?searchterm=mating+station) and inbreeding is never an issue.

 

[Truble]

Brother Adam crossed different races so this is different to crossing high performing lines within a race.

The genetic principals are exactly the same.
Taking, for example, the trait of long flights for forage from Apis mellifera sahariensis and establishing that trait in your current Buckfast line/strain involves no different principals from adopting a characteristic within a line of the same race and adding it to another line of the same race. They are all the same species.

 

[Fusion_power]

Have you thought about indexing your colonies to see how many diploid drone eggs the queens produce? It should be fairly simple to photograph a comb with eggs, then come back to that comb 6 days later and photograph again to see how many cells have larvae vs how many had eggs.

I concur re your comment on pedigrees, I would need a lot more data to enable such an analysis. However, my comment was that it would be interesting to see the analysis done, not necessarily that it should be done using my bees.

 

[B+.]

Have you thought about indexing your colonies to see how many diploid drone eggs the queens produce? It should be fairly simple to photograph a comb with eggs, then come back to that comb 6 days later and photograph again to see how many cells have larvae vs how many had eggs.

I use the same template that I use for the pinprick test (http://www.beebreed.nl/mal-pintest.pdf). the number of empty cells in May indicates the inbreeding but you take several readings and average them.