Defining heterosis Heterosis is based on what we call dominance genetic effects, and these effects result from interactions between the pairs of alleles at all of the genes that influence a characteristic of interest. Indeed, the utilisation of dominance genetic effects is fundamentally based on combinations at every level — of species, of lines within species, and occasionally even of individuals within a population.
While utilising heterosis can be an attractive strategy for improving traits that exhibit low heritabilities, any advantage that might be derived is only temporary. Since these interactions depend on specific combinations of alleles, they cease to exist during the formation of eggs and sperm.
So heterosis is, unfortunately, not something that can be inherited or passed along from generation to generation. Hybridisation vs crossbreeding a fuzzy distinction Hybridisation, in the strictest sense, involves the crossing of related species.
Some examples include crossing striped bass with white bass, channel catfish with blue catfish, or Nile tilapia with blue tilapia. In contrast, when distinct stocks, lines or varieties of the same species are crossed, the most appropriate term is crossbreeding, with the resulting offspring referred to as crossbreds. Nonetheless, some researchers use the term hybrid even when both parental lines are from the same species.
In fairness, the distinctions between strains, races and species are often blurred to a point where crossbreeding or hybridisation are essentially indistinguishable. Sometimes, producing these crosses is easily accomplished, but occasionally a lot of work is involved. Often, progeny must be evaluated on a cross-by-cross basis to determine how the alleles involved will interact to impact production performance.
Depending on the cross one is pursuing, it may be necessary to capture wild broodstock or resort to hormonal injections or implants. A hybrid North American sunfish Whenever hybridisation or crossbreeding is to be practiced season after season, the need to maintain access to each parental line is unavoidable.
With this need comes the requirement for adequate facilities to house sufficient numbers of individuals. Care must also be taken to avoid inadvertent mixing of distinct lines within species. So why bother? The resulting benefits can include not only heterotic gains but also the combination of desirable traits from parental lines. Occasionally the production of monosex offspring is also possible by crossing closely related species that exhibit distinctly different sex-determining systems.
Once they are produced, evaluating hybrids or crossbreds of aquatic species can usually be a fairly straightforward process. The best approach to these evaluations involves a design that includes both pure lines and their reciprocal crosses line 1 females by line 2 males, and line 2 females by line 1 males. Even more complex designs, involving multiple parental lines, can be accommodated if suitable incubation and rearing facilities are available.
Mating designs involving more than two lines are typically referred to as diallel crosses. They may also grow larger than either of their purebred parents. Not all livebearers can hybridize, a Guppy and a Platy for example, cannot cross.
These, however, can:. Not all Cichlids can hybridise either, and crosses are often unsightly and undesirable, the exception being the Blood Parrot Cichlid and the Flowerhorn. It is NOT encouraged to breed these hybrids and put them into the pet trade, it only dilutes bloodlines. It must be noted that many of these crosses are highly aggressive fish and are best kept in species tanks or with equally mean-tempered robust tank mates.
The only real exception is the Blood Parrot, but it can still pack an attitude if it wants to! You need to be really careful when buying African Cichlids, specifically Mbunas , from pet stores as many on the market are hybrids, if you want genuine purebreds it's best to go to fellow breeders or at least enquire further about their history.
Never buy African Cichlids from a tank labeled "mixed Cichlids", you don't know what you're going to end up with. The gender of a dimorphic fish is easy to identify, and you can identify the gender by their reproductive organs, which are shaped differently. Their size, shape, and color are all unique, so you can easily tell them apart. There is one simple difference between the male and female; the males are larger and more vibrant. But, never say never.
There is a way to tell the difference. You can tell the difference between the male and female fishes by keeping a close eye on their organs during spawning. The shape of the organ would help you easily identify which is which. Before you go on a spending spree to pick a fish for breeding, you can remember this to identify you got each of the sexes. Once you have the fish picked out, it is time to see if your fish tank is ready for breeding, regardless of crossbreeding or interbreeding.
You can use the checklist below to make sure the conditions are met;. Additionally, I would recommend keeping the fish tank with sand and some soft rocks. I suggest keeping a soft base because it would encourage fish to mate. Harder surfaces could hurt the fish and the eggs. You should also consider the environment required to raise a fry.
Most people use a sponge to create the right type of current for raising a fry. Moreover, I would recommend keeping the breeding tank in a shaded area. Bright lights could discourage or disrupt the mating. I would advise feeding your fishes protein-rich food because it will make them healthier in the days to come. A healthier spawn of fishes can increase the chances of successful breeding.
Continue feeding them for 3 to 5 days because it will give them enough time to gain their strength. Lastly, you have to maintain water quality. This means maintaining pH levels, temperature, etc. Keep the water tank at a temperature that is good for crossbreeding or interbreeding.
While you are going through the checklist, research about your fish. Every species requires different conditions to crossbreed and interbreed. This can lead to quicker breeding. Yes, a fish can be crossbred, but with one condition. The fish being crossbred need to be closely related. The fishes born out of this are called hybrids. Some female fish can give birth to a young, and healthy fry.
Alternatively, the other bunch of fish relies on one mating session to produce several babies even after the male is gone. Basically, it keeps the sperm and reuses it over a span of 8 months to give birth to several fry. The year was , and one red devil cichlids fell in love with a trimac cichlids.
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