Did67 wrote:I just flew over this thread - chance, yesterday, in Strasbourg, I was asked to give a topo on the subject. Let's go back to basics - as always, before arguing over recipes, it's better to have a few basics.
A) Asexual reproduction
Many plants reproduce asexually: grafting, cuttings, layering, stoning ...
It is then a question of cloning: the plant obtained is genetically strictly identical to the ancestor (except in rare cases of mutation which has occurred in the meantime).
Even more surprising: we can consider, for example, that all the Burlat cherry trees in the world or all the "Clementines" are a "piece" of a single being, dispersed with each grafting; it's a "piece" of the ancestor that we grew up elsewhere ...
In the vegetable garden, this is especially the case with potatoes, garlic and shallots. In the ornamental garden, plants are added whose stumps are "exploded" ...
Advantage: strict character conservation
Disadvantages (I think you have noticed, nothing is perfect in this world):
- no biodiversity: if a disease "adapts" to this variety, everyone in the world will be sensitive to it! It is not nothing that it is in viticulture and arboriculture that pesticides are used on a massive scale and that the switch to "organic" is not always easy ...
- little by little, virus-like diseases (more or less embossed leaves, nannies, etc.) take hold, often peddled by aphids (or other biting-sucking); these diseases are propagated by vegetative propagation.
For this reason, the "breeders" proceed by multiplication of meristems, free from viruses, that one can, by suitable nutrient solutions, "elevated" to reconstruct a healthy individual. That we then propagate with care (disinfection of instruments, grafts, etc.). Nurseries are controlled. The label guarantees that the plant is healthy.
[Meristem culture is the cultivation of the heart of a bud, where the "undifferentiated" cells multiply, before becoming specialized cells constituting the wood and the different parts of a branch or a leaf or a flower). It turns out that in these meristems, even in an infected tree, the cells are not.
In short, know that without special precautions, there is a risk of slow "degeneration" of the variety. This is inevitable, except in very specific situations (at altitude, for example, absence of such aphids which carry the various potato viruses). So maybe nico will be spared ??? And he'll tell us, but no guys, no problem, I've been doing this for 10 years, it works! And he will be right. [Well, he can't have that shit about his situation either, let's be a bit of a nice gamer!]
Grafting (tomato, ...) can be a very elegant way of "bringing together" in a plant two interesting characteristics: for example, we will use rootstocks whose roots are resistant to nematodes (parasitic non-ringed worms and vector diseases) but whose fruits would be appalling (small, disgusting, even toxic) and graft on it a heart of beef, whose roots are very sensitive ...
B) Sexual reproduction
The big advantage: remixing of genes with each generation, which allows to evolve, to adapt.
The downside: as a rule, the offspring only roughly resembles one of the parents (the mother plant) ...
1) Cash
As a rule, species are sterile with one another. It is the very principle, the definition, of a species [all fertile beings among themselves, but which are not fertile with another species].
Except that it gets harder: some species are still close enough for a hybridization
interspecific (between different species) is still possible. In animals, the case of the horse and the donkey are known. I wonder if the wolf can not cross with certain dogs ??? Etc ...
In plants, certain crossings are possible: mustard and ravenelle (a kind of wild mustard).
The case of the squash x coloquinte crossing is a false friend! Our symposia are ...
squash decorative. Selected for that. Care has not been taken to rid them of the genes leading to the synthesis of the toxic bitter substance of most wild cucurbits. So it is not an interspecific crossing, but a crossing between two very different types of squash (a bit like a chihuahua remains a dog, even if it is very different from a German shepherd or a Beauceron).
I did not do the necessary research [because I am far from knowing everything !!!] to know if the kale and Brussels sprouts are two different species. And if, due to a relative proximity, interspecific crossings are possible. Sometimes it is possible but rare. Sometimes it's impossible but in the lab we manage to create interspecific hybrids: casseilles, brugnons, triticales (a cross between wheat and rye) ...
Subject to the lack of possibility of interspecific crosses, you can cultivate two
cash different one next to the other without risk. How you can breed wildebeest and gazelles in the same park! Latin names allow you to know if they are different species: the two "names" are then different; we sometimes add ssp. - for "subspecies" = subspecies - "this or that": the colocynth is a Cucurbita pepo, the squash is Cucurbtia pepo, the courgettes are ... Cucurbita pepo like spaghetti squash or patties ...! So all of this can intersect. The squash is sometimes indicated: Cucurbita pepo ssp.pepo]
2) Varieties
Varieties are to plants what breeds to animals are. In principle, a variety A (with such and such characteristics that make it appreciated) can cross with a variety B (which has others, which make it appreciated for other reasons) .
In general, when we sow, we would like to know if it is A (resistant to cold, for a spring sowing) or B (resistant to drought). We are not going to sow B in March and A in July. And an AB hybrid (more very resistant to cold and only a little resistant to drought) will not necessarily interest us, neither in March, nor in July! Not to mention here the taste characteristics !!!
a) autogamous species: these are the species of which, for certain reasons, the pollen fertilizes the pistil of a flower of the same plant ... So it is the genotype A which fertilizes the genotype A (the genotype is all just the collection of genes).
Note that this is "inbreeding" - with its flaws (they are more crippling in animals).
If the breeder (breeder) has taken care to stabilize the characters of the variety, at the end of a long process, at least ten years of selection, then we have conservation of the varietal characteristics.
In principle !
Because obviously, it's more complicated! Strictly self-pollinated plants are rare. These are called "cleistogams", whose fertilization is done "internally", before the opening of the corolla. Even if foragers pass after opening, and forage, and try to fertilize, it's too late, fertilization has already taken place.
This is the case with beans and, for the most part, tomatoes (it depends a little on the growing conditions).
This is the simple case where we can give ourselves to heart and multiply without too much difficulty. Finally, it is not that simple! You have to label properly, keep ...
The bumblebee has, in tomato greenhouses, a shaker role rather than a pollinator. Even if it can fertilize flowers that have escaped "internal" fertilization.
Are self-pollinated, among others: beans, peas, lettuce, tomatoes, eggplants, peppers, soybeans, peanuts, beans, lamb's lettuce ... (and most cereals: wheat, oats, rye, barley ...)
As autogamy is never strict (it is 95%, sometimes 99%), there is a slow drift, through accidental crossings.
The seed producers therefore make a "conservative mass selection": before they reach maturity, they remove all the plants which do not resemble the precise description of the type of the variety. Even, regularly, leave carefully selected ancestors, therefore "very pure".
Without knowing it, "fans" of old varieties "exploit" the meticulous work of the ancestors of our current seed companies, Vilmorin, Caillaux, Clause ... Few old varieties are in fact "authentically" peasant! This is mainly found for the few cleistogamous species: tomatoes, beans ... Where there, the "stabilization" went by itself! For the most part - I may forget one or two other species - the heirloom varieties are the result of a selection made by companies in the 1800s and beyond, sometimes with the involvement of "gardeners", who tested. then adopted what was then new !!! [200 years later, "novelty" remains one of the classics of especially professional seed catalogs!]. FYI, professional tomato seed catalogs in the early 1800s included 2 or 3 varieties. I will not philosophize any longer, but there is obviously reason to wonder about our whims! After, each his passions. I know some who collect stamps ... Others beer capsules (but there, I guess the usefulness at the level of the step before!).
b) allogamous species
Nature often favors cross-fertilization. By different "tips": delayed maturity of the pollen and pistil, separation of the male flower and the female flower (on the same individual - maize - or on different individuals - kiwi), pollination by the wind, pollination by insects, form flowers ...
In this case, except in special cases, the probability that a variety A pollinates the flower of a variety B is then high. And so, if in the fruit that grew on B we take seeds, we have seeds AB, and the next year, the plant will be AB (somewhere between A and B). No forecast is possible. A friend told me this weekend (by chance!) That they have a couple of friends, she blonde, he black, who have three children: one is "typically white", the other almost black and the third typically café au lait !!! It is the chance of the recombination of characters.
Are allogamous: cucurbits (cucumbers, melons, squash, pumpkins, pumpkins ...), celery, parsley, onions, carrots, crucifers (cabbage, turnips, radishes ...), chicory, chicory, fennel, parsnips, corn, beets, spinach ...
The production of seeds with conservation of varietal characters (therefore what interested us in such a variety that we have cultivated) is only possible in two ways:
a) a sufficient distance from any plant to another
variety of the same species (including wild plants of the same species - wild carrots for example); order of magnitude: 500 m to 1 km.
b) or a bagging of the flower chosen as female, which one preserves from a cross pollination (attention for the anemophilous plants, fertilized by the wind, it is necessary a gauze which filters the pollen); fertilization is carried out manually with pollen of the same variety, and closed until maturity ...
Here too, however, a conservative fertilization is necessary (it is even more so in the case of distance, because if 500 m is a standard, no one will prevent a drone Olympic champion from losing his way for 2 or 3 km Without being champion, it can be embarked by a gale ... Simply, it is rare!
3) Diseases
It is not well known, but some diseases are transmitted by seeds (usually on the outer covering of the grain).
The case of ergot in rye (today almost eradicated, thanks for the surface treatments) is known (I believe that it was in Bagnol sur Cèze that there was a famous case of "madness" attributed to witchcraft, which today we know was ergot - a fungus whose slightly modified extract is ... LSD!)
Professional seeds, even "organic" seeds, are disinfected. The law is extremely severe at this level. And rightly so. When you buy a seed, you don't want to buy the parasite that goes with it!
4) F1 hybrids
The F1 hybrids - first generation - are the result of a cross between two pure lines, each of which has qualities that we want to bring together (line A of tomatoes, very round and red, but puny; line B early and productive) ... it is two lines are pure, the crossing "will contain"
necessarily these 4 characters combined: red and round fruit, productive and precocious variety ...
But only in the first generation. Hence the F1 (the F comes from descendants, filius in Latin).
Because in the next step, it is the "big mess" of the lottery and the chance.
Contrary to what I often read, F1 hybrids are not sterile.
There is only this "disjunction of the characters" which will make that in the descent we will have everything and anything: round tomatoes and others which are less so, red tomatoes and others which are not, early and late tomatoes, productive and puny ...
Sometimes we use wild tomatoes, ridiculously small but resistant to mildew in one of the lines, and we can therefore expect to get ridiculously small feet, like wild ...
It would be time to stop raving about hybrids, knowing that it is a "mechanical" selection that has nothing to do with GMOs. But that this made it possible to introduce very interesting germs (such as wild resistance genes). This is not hybridization, which is a very natural occurrence (all botanical orchids are hybrids !!! Most stable varieties were initially a hybrid). These are the selection criteria that make us prefer tasteless and hard tomatoes like pebbles to tasty tomatoes, quite simply to deliver you tomatoes from Morocco all year round since the consumer buys! One could imagine "hybridizing" the best tastes to obtain "taste bombs" (probably impossible to transport!). Technically, it is quite possible by putting the package on this criterion.
[For your information, there is currently an explosion of hops with very specific flavors: citrus, chocolate, etc ... which are the fruit of hybridization, followed, in this case, by vegetative propagation]
That at the price, we agree, of a buyout of seeds.
It would be, in areas with low or medium pressure of mildew, much more ecological and much cheaper than throwing this crap of "Bordeaux mixture" !!!
transfer reims[it's a little more complicated, because the resistances are bypassed by the very rapid adaptation of the fungi; it takes in fact a combination of different resistance genes - 3 or 4 minimum - so that the milidou does not "crack" the code too easily!]
Try to understand the "greenies" sometimes.
it sticks too much and only the tops come! Which explains why I let it go to seed, but I do not despair of seeing my land worsen over the years and being able to finally get them out ... at this stage, after the various hybridizations to which you refer the result should be interesting. Can not wait to see it...
