Hybrid Vigor vs. Natural Vigor

[Countryboy]

In another thread the comment was made that if you start inbreeding then hybrid vigor will decrease. Folks keep talking about the need for diverse stocks, which will just create hybrids.

Is hybrid vigor a good thing with bees? The only instance I can think of where hybrid vigor would be of any benefit to a beekeeper involves annual requeening of every hive.

I'm familiar with hybrid vigor in plants. Two strains are crossed, and the resulting offspring has some benefit that is better than either parent possessed. However, if you replant a seed from the plant with hybrid vigor, the new plant will not grow true to parent. Quite often, the plant is far inferior to the two original grandparent strains.

Are bees this way? Are we breeding hybrid vigor into our bees, and have really good queens for one generation, and as soon as they supercede, we end up with duds? To prevent this, we are stuck in a constant cycle of trying to bring new genetic strains in, so that every generation exhibits some hybrid vigor.

There are also hardy varieties of plants that have natural vigor. These plants grow true to seed, and every generation retains the traits of the parent stock. These are often called heirloom varieties, as you can replant generation after generation of seeds.

How do we develop good hardy strains of bees with natural vigor, instead of trying to continuously find bees that exhibit hybrid vigor in each generation?

[Michael Bush]

It's a philosophical question I guess. My grandpa used to say the only thing horses were good for was breeding mules. But someone still has to breed horses... The hybrid is not a stable "race" while the race has more stable traits and is more sustainable. In my experience, with bees, hybrid vigor usually means they are vicious.

[Michael Palmer]

In another thread the comment was made that if you start inbreeding then hybrid vigor will decrease. Folks keep talking about the need for diverse stocks, which will just create hybrids.

Is hybrid vigor a good thing with bees?

I'm familiar with hybrid vigor in plants. Two strains are crossed, and the resulting offspring has some benefit that is better than either parent possessed. .

Are bees this way?

As far as hybrids go, it's a matter of opinion. Some breeders want pure strains. I prefer my mutts.

But breeding bees is different than breeding plants and horses, etc. Queens mate with many drones, not one. So, the diversity you speak of is important in both pure strains and hybrid strains. The diversity comes into play via the many drones of different stocks...either pure strains or mutts.

Have you read or heard Dave Tarpy's work...NC State. He uses chalkbrood as an example. If a queen mates with one drone, and that drone carries genes for chalkbrood resistance, then that resistance is transferred to the offspring. If he doesn't carry the resistant gene, then no resistance. So, he calls it the 50/50 rule. Mating with one drone, or multiple drones of the same genetics equates to a 50/50 chance of inheriting chalkbrood resistance.

Now, if the queen mates with many drones of different genetics, and some of those drones carry the genes for chalkbrood resistance, the colony is more likely to be resistant to chalk. It doesn't take every bee (line) in the colony to be resistant for the trait to be expressed.

So to me, it's more about the diversity of the drones than it is about hybrid/pure races. Does that make sense?

[AmericasBeekeeper]

If you research Buckfast Abby, they have a breeding program that starts with diversity. After many years when a hybrid is set, they are numbered, that genetic group is distinctly maintained. Those queens are bred with drones from the same group in different hives. Genetic depression is maintained by having multiple sources of the same numbered stock.
They do have the advantages of isolation to prevent unexpected crosses, and the operation has spread to several countries improving diversity and heterosis.
"Today the Buckfast bee from Buckfast Abbey contains heritage from mainly A.m. ligurica (ligustica) (North Italian), A.m. mellifera (English), A.m. mellifera (French), A.m. anatolica (Turkeish) and A.m. cecropia (Greek). The Buckfast bee of today may also contain heritage from A.m. sahariensis and A.m. monticola."
The process is continuing today and there are new groups that appear better than the original. Since the threats are changing, the genetic resistance must change. The USDA stopped imports back in 1922 so there is not much diversity and a lot more inbreeding after 88 years. They do recognize the problem and allow in frozen sperm that does not show any titers of diseases (that we really want to breed for resistance).

[Oldbee]

"Genetic depression is maintained by having multiple sources of the same numbered stock."

First time I have seen the term,.genetic depression, unless it is about mental problems. Found one reference about isolated populations of panthers in Florida. > http://www.defenders.org/programs_an...depression.php

Wiki has something regarding inbreeding depression. > http://en.wikipedia.org/wiki/Inbreeding_depression

[deknow]

i've always thought of hybrid vigor as nothing more than a "lack of inbred characteristics".

there are queens you can purchase that are true hybrids....distinct inbred lines are crossed. these lines are _really_ inbred....they can't support themselves, they can't produce enough brood to grow...frames of brood and honey have to be constantly fed into these colonies. compared to the inbred colonies, the first generation hybrid shows "hybrid vigor".

deknow

[deknow]

Mating with one drone, or multiple drones of the same genetics equates to a 50/50 chance of inheriting chalkbrood resistance.

but:

Now, if the queen mates with many drones of different genetics, and some of those drones carry the genes for chalkbrood resistance, the colony is more likely to be resistant to chalk.

ok....by what you describe, we can assume chalk resistance to be dominant...only has to be inhereted from one parent. (i'm sure chalk resistance is more complicated and variable than this, but let's just keep it simple).

so: Queen A does not carry chalk resistance, and she mates with 20 drones, all from different colonies/genetics. 10 of the drones carry chalk resistance, 10 don't. 50% of the workers in this hive carry chalk resistance, as do 50% of the queens. 0% of the drones have chalk resistance (CR).

Queen B is the daughter of queen A and one of the drones that carries CR. 50% of her female offspring carry CR, 50% of her drones carry CR. Let's assume that 50% CR results in observable, desireable resistance to chalkbrood (i don't know if that's a reasonable assumption...but for the sake of discussion)

Now, a queen mating with a single drone from Queen B's colony has a 50% chance of inheriting CR...but mating with 2 drones from that colony could lead to 25% chance of all female offspring to carry CR, 25% chance that none of the female offspring would carry CR, and a 50% that half the female offspring would carry CR.....so, again assuming that 50% and 100% CR is significant, there is a 75% chance that the resulting colony will be chalkbrood resistant _if_ the queen mates with 2 drones from the same hive (vs 50% is she mates with one drone).

does this make sense? am i missing something?

deknow

[camero7]

Used to raise sheep for many years. Used cross-breeding all the time. There is definitely hybrid vigor in animals. Well documented and sound animal husbandry. Go out west and see all those white face, black steers. True hybrids from Herefords and Black Angus. I would think it would also translate to bees.

[AramF]

Hybrid vigor is done by taking two pure lines, each with disirable characteristics that are lacking in the other, and breeding them together. As the results the dominant qualities from each line will come through making a good overall hybrid. Breeding the hybrids back to the original parental line or to its siblings is unlikely to give the same results.

Does that mean that pure line are not good. Well, let's think of leghorn chicken. That bird was developed by many generation of inbreeding. I doubt anyone will say that they are inferior because they are inbred. In fact they are so inbred, that all of the lethal genes have been taken out of them. They can inbreed for many generation with very little depression.

Depression comes from focusing on desirable traits, while ignoring selection for lack of undesirable. So if in bees you are selecting for a quick spring buildup, you might ignore the resistance to varoa trait. In the end you end up with a queen that lays non-stop, but all of her progeny is deformed. You need to select for everything you desire and lack of everyting you do not desire. Only then the inbreeding depression will not occur to you.

Unfortunately it means that from a desirable queen you need to raise hundreds of daughters and select maybe 5-10 for the next generation. On top of that you need to fight multiple mating from unknown drones and the fact that drones from different hives can enter your hive unnoticed. How you can guarantee that your drones are pure? I guess selecting by queen performance and hope for the best as far as the drones is probably the only way to go.

[ChristopherA]

The biology is very impressive with a bee. Which would be the best source of information on how the queen bee process the genetic materials?

It kind of confuses me to a point. The sperm within the queen mixes thus producing a brood of resistant bees? I wonder how it is processed and can use one of my hives in which the color traits of the queen brood are different colors within the same hive. Some are very yellow/orange while other are black. These are Carnie/Russian Hybrids hives.

Any help would be greatly appreciated.

[RiodeLobo]

I believe that one egg and one sperm= one bee (worker). But say that 50% of the drones that the queen mated with carried resistant genes than a certain percentage of the workers would express those genes. Every worker in the hive does not have to be resistant to have a hive that is. The coloration is an example of that. Different father means different genetics in the hive every worker is not equal, some will have different colors, hygienic behaviors and resistant traits.

That is my take on it anyway.
Dan

[AramF]

Ok, so the sperm mixes, but it does not blend. So the sperm from drone 1, drone 2, and drone 3 will produce offspring which are a combination of drone1and queen, or drone2 and queen and drone3 and queen, not drone1,2,3 and queen. Therefore all the worker bees are at most full siters, at at least half sisters (With a common mother and different fathers). THerefore your assumtpion that they would be resistant just because there are different drones is not based on mechanics of genetics.

The reasons you have different collors is as follows. If one drone was orange but the other one was black, the workers that were fertilized by orange drone's sperm will come out orange and the other ones black. I realize that you are not familiar with genetic, so I will not add the fact that the queen herself can be heterzygous for color variation, but I think you get the jist of it. There is no blending of sperm, each sperm cell keeps the characteristics of the drone that produced it. I doubt the queen can control which sperm fertilizes her egg, though she can control whether or not the egg is fertilized.

[Michael Palmer]

ok....by what you describe, we can assume chalk resistance to be dominant...only has to be inhereted from one parent. (i'm sure chalk resistance is more complicated and variable than this, but let's just keep it simple).

I was only using this as an example, trying to keep it simple as you say. Don't assume anything. I can't remember if he said it was a dominant trait or not. If so, then it wouldn't matter who the queen mated with. At any rate, the idea is that the colony has a better chance having some degree of resistance to chalk depending on which drones the queen mated with. If she mates with only one drone the chance is 50/50. The more drones she mates with from different stocks the greater the chance the colony will show some degree of resistance, since every bee in the colony doesn't have to posses those genetics.

[Michael Palmer]

The reasons you have different collors is as follows. If one drone was orange but the other one was black, the workers that were fertilized by orange drone's sperm will come out orange and the other ones black. I realize that you are not familiar with genetic, so I will not add the fact that the queen herself can be heterzygous for color variation, but I think you get the jist of it. There is no blending of sperm, each sperm cell keeps the characteristics of the drone that produced it. I doubt the queen can control which sperm fertilizes her egg, though she can control whether or not the egg is fertilized.

That's right. But there are both black and orange bees in the hive. And suppose it only takes some black bees to either resist...maybe the wrong word...better to say clean up the chalk. As long as there are the black cleaner up bees, no matter the %...see?

[Countryboy]

In my experience, with bees, hybrid vigor usually means they are vicious.

The F1 generation should exhibit the hybrid vigor, but I have heard several reports of the F1 generation being very gentle, with subsequent generations turning vicious. (aka not growing true to parent) Russians and Buckfast bees have reputations for turning vicious after supercedure. Supposedly, the original German Black bee, when it crossed with the Italian, created a bee that was absolutely miserable. (The original German Black bee was supposedly gentle, but did not get the mean reputation until after crossing with the Italian.)

I am not familiar with hybrid vigor being limited to just one trait, so I have no idea why people are using single traits as examples.

I'm not interested in breeding for specific traits in a bee. I want my end result to be good quality hives. Take Mike Palmer's breeding approach - instead of trying to isolate individual characteristics, simply breed from the strongest hives you have coming out of winter. I want to breed queens with a package of overall good traits.

If I have a queen from a good hive, and I raise daughters from her all mated in the same mating yard, those daughters 'should' be similarly mated as they should have similar exposure to drones from the same hives. However, individual performance from each daughter will vary. Some will be good like the parent, and some will be duds.

To my way of thinking, that sounds just like how an F2 (or F3 or F4 or F5) generation works.

To my way of thinking, shouldn't we cull the undesirable F2 stock, and breed from the members of the F2 generation that displayed the overall characteristics we like? This is what most folks try to do - breed from the best stock.

If we keep breeding the few stock in each generation (F2, F4, F5 etc) that exhibit the overall characteristics we like, eventually the rate of occurrence will increase. We will be refining and breeding for natural vigor - a vigor that is apparent in every generation.

However, if we keep bringing in new stock, which will work to breed out natural vigor by creating hybrids....right?

Yes, we want to have a large gene pool at the very beginning so that we have the best chance of finding the genetic combination we like. Once we identify good stock, shouldn't we stop bringing in new genetic material and concentrate on refining what we have?

Maybe I'm naive, but I consider the talk of inbreeding to be less of a problem than folks make it out to be. Normally you need several generations of one family line breeding back to back before you start seeing problems, and a little mixed blood (supplied by feral drones) cleans up the problems. Once you have a good base stock, you should be able to bring in small amounts of better/good genetics to improve your stock and prevent serious genetic bottlenecks.

To limit inbreeding, you have to marry someone more distant than a 3rd cousin. (Yes, I have seen closed marriage societies that originated from a select few families - and yes, even if they marry past the 3rd cousin the genetic pool is so limited that they have higher rates of dwarfism and retardation, but the vast majority of Amish are still pretty good stock.)

[AramF]

>>>If I have a queen from a good hive, and I raise daughters from her all mated in the same mating yard, those daughters 'should' be similarly mated as they should have similar exposure to drones from the same hives. However, individual performance from each daughter will vary. Some will be good like the parent, and some will be duds.<<<

Well, I think breeding many and selecting the ones that behave the way you want is a good idea. The only issue is that this was the management style of the people who ended up with africanized hybrids from drones that wondered into the "same mating yard." But you can always hope for the best.

Commenting on the bees turning nasty after two generations. I bet that gentle behaviour is what Darwin would have called a "monstrocity" caused by human selection in bees. Once we start hybridizing, the bees begin to revert back to their natural state as more variety of genes become available. If you let all of the fancy white, brown and blue breeds of pigeons breed at their leisure, pretty soon you end up with a grey street pigeon. If you let Rhode Island Red cock cover a Leghorn hen, then 90% of daughters want to incubate eggs, while none of the parents ever go broody.

Gene interactions are extremely interesting, but given bees non-selective breeding behavior with many drones, even if you get some amazing queen, 2 to 3 generations down the road, you are probably going to end up with a fairly average daughters. So breeding many and selecting a few that work for every generation is probably a more successfull strategy then genetic selection.

[deknow]

At any rate, the idea is that the colony has a better chance having some degree of resistance to chalk depending on which drones the queen mated with. If she mates with only one drone the chance is 50/50. The more drones she mates with from different stocks the greater the chance the colony will show some degree of resistance, since every bee in the colony doesn't have to posses those genetics.

i understand the example (and understand that it is simplified for discussion sake).

but

unless you are working with "pure strains" (in which desired traits are fixed from both the mother and father side), it doesn't make sense (to me, this morning).

every bee in the hive does not have to carry the desired trait (CR), and every drone from the hive does not necessarily carry CR (let's assume 50% of drones from a single colony carry CR).

a single queen mating with 2 drones from such a colony has more than a 50% chance of inheriting CR..the same chance she has if she mates with 2 drones from separate colonies (if each colony produces 50% drones with CR and 50% without). increasing the number of drone source colonies doesn't change the chances of inheriting a specific trait (or gene) _unless_ some of the drone source colonies have a higher incidence of these traits than others.

the logic you are presenting works for organisms that have single matings...but bees are so much more complex, and most of us aren't dealing with pure (II) strains (thank god...it just isn't how "bees work").

deknow

[Michael Palmer]

Dean, I don't know what else to say about it. I find the study to be understandable. So, read it yourself....

http://www.ncbi.nlm.nih.gov/pmc/arti...f/12596763.pdf

[valleyman]

I have read some very confused information written by some who doesn't understand the mating process and the laying procedure of the Queen. Then there are some that seem to understand and have not commented back. Some have stated situations that could only be done with genetic manipulation, and could never be accomplished with just breeding.
I completely understand the hybrid vigor concept in animals as I bred seedstock cattle for many years. As has been stated previously it does work but only for the current generation and is not passed on into the next. let me throw a little tid bit for humor in here that is really true. In the cattle business, and I assume most other animals. It is if it works it is line breeding, and if if comes out bad it is inbreeding. With the best of my limited knowledge I believe that when you have differing genetics that can mate and produce offspring, then the offspring will be sterile and unable to reproduce. My example being The mule which is 1/2 horse and 1/2 ass or donkey. I would imagine if the honeybee crossed with a bumblebee then the same could happen. The horse and donkey are both equine but genetically far apart. This is in my opinion what the term hybrid is best understood as. But hybrid can be applied to any crossing of genetics, and their offspring.
With bees the queen is mated to many drones. So if the mating is not COMPLETELY controlled you can't predict with any certainty what the offsprings charateristics will be. The only way to be 100% sure is with II or AI in my world, and only then after the drones have been dna tested. Can anyone tell me how to COMPLETELY control the drone fathers and their mating with a queen?
When you speak of hybrid Russians, for example, you are merely talking about a pure Russian queen that is open mated, thereby creating a hybrid offspring of 1/2 Russian and 1/2 whatever sperm she uses on that particular egg. BUT, if the sperm she uses should be from a pure Russian drone is that offspring a hybrid? In my opinion no.
The mutts that we speak of are generations of crossing genetics, and that is only good if the mutts we are keeping have developed good traits thru generations of naturally crossbreeding, and sometimes I'm sure, line breeding.
So this is one reason that I decided to go to the pure Russian genetics that I now have their traits are/should be more across the board predictable. As are the strains that people like Russell Apiaries, and BWeaver, just to name a couple for examples, have produced by either genetic manipulation or years of breeding for the best.
I hope that I have thourghly confused some of you'll as I think I am confused myself.
I hope Mr. Robert Russell will chime in here,hopefully he has since I started my post.

[Countryboy]

every bee in the hive does not have to carry the desired trait (CR), and every drone from the hive does not necessarily carry CR (let's assume 50% of drones from a single colony carry CR).

a single queen mating with 2 drones from such a colony has more than a 50% chance of inheriting CR.

But in order for the queen to pass on the chalk resistance to the next generation, a new queen must be raised from an egg fertilized with sperm from a CR drone. If you don't do that, you just have to hope and pray your virgins queens keep finding some CR drones to mate with.

It is if it works it is line breeding, and if if comes out bad it is inbreeding.

I understand the concept of line breeding. What I don't understand is why people keep wanting to continuously add new genetics to water down the line, thinking they will get a stronger line overall.

How hard is it to inbreed bees if someone wanted to? Does it actually happen very often, or is talk of inbreeding bees just more fear mongering with little actual basis?