What does line-breeding actually mean?

[My Green Pets]

Hey all, I remember reading on here awhile ago about how some paphs like rothschildianum used to be super slow-growing, hard to bloom and easy to kill, but thanks to line breeding, much easier plants have been produced in recent years.
So I am trying to do the same thing with my cattleya rex plants, they are also slow-growing and highly susceptible to rot, very easy to kill even in decent growing conditions. What do I select for when making sib crosses? Right now I look for:

• shortest time from flask to bloom
• quality/size of flowers
• vigor
• size of plant (preferring compact)

That said, I guess that just the fact that these plants have survived from flask to bloom in my care says something about them.
Curious if anyone had any additional insight into this line-breeding thing.
Thanks, WG

 

[eds]

Line breeding is simply taking a lineage of plants through multiple generations and selecting for particular qualities. As you said survivability and ease of flowering tend to get inadvertently selected, if not intentionally, as the first plants to flower from a cross tend to be the first to get crossed/selfed again, as long as the flowers are deemed to be of a good enough standard.

Every so often, or if certain faults are seen within the line, you might outcross to another unrelated plant to try and introduce new desirable traits and then select for them on top of your current desired traits.

 

[My Green Pets]

Thank you ed!

 

[littlefrog]

I'd breed for vigor first. One of my early mentors insisted that he would keep the first 10 to bloom (I think it was 10), and sell the rest no matter how good they were. Vigor was his first priority. Makes sense, since you can't have good flowers on plants that don't grow well.

In your case, if you have poor growth and your conditions are good, you should probably seek to do some outcrossing. If the alleles aren't there in your parent population, they aren't going to spontaneously appear no matter how much line breeding you do (well... they might... but your chances are really really poor). Get some pollen from the native habitat, if possible?

 

[eds]

Totally agree with the above but there is a big difference between line breeding a population of a species and producing complex hybrids.

I am currently breeding Echinopsis hybrid cacti. If I just keep the first 10 to breed I will end up with some brilliantly growing cacti but with boring flowers! The ones I want are much more likely to be in the other 60+ plants per cross so I need to grow them all to flowering size. However I won't select a plant that hasn't flowered in say 4-6 years or struggles to grow on its own roots so that is my nod towards the vigour element.

 

[Phred]

Hey all, I remember reading on here awhile ago about how some paphs like rothschildianum used to be super slow-growing, hard to bloom and easy to kill, but thanks to line breeding, much easier plants have been produced in recent years.
So I am trying to do the same thing with my cattleya rex plants, they are also slow-growing and highly susceptible to rot, very easy to kill even in decent growing conditions. What do I select for when making sib crosses? Right now I look for:

• shortest time from flask to bloom
• quality/size of flowers
• vigor
• size of plant (preferring compact)

That said, I guess that just the fact that these plants have survived from flask to bloom in my care says something about them.
Curious if anyone had any additional insight into this line-breeding thing.
Thanks, WG

Hello My Green Pets
I love this subject but there is so much misinformation/misunderstanding surrounding it. There’s a saying, “Line breeding is whatever works and inbreeding is whatever doesn’t.”
Although you’re asking about plants the same principles are more commonly applied to animal breeding. Interestingly, this whole concept started with crops like wheat and then cattle breeders started applying the concept in their programs.
First, anytime you breed plants with similar ancestors it’s called inbreeding. Inbreeding provides the opportunity to combine or double up on traits. Inbreeding is as good as it is bad.... If you have good traits and you double up on them you get good and if you have bad traits and double up on them you get bad. The difference between inbreeding and line breeding is the degree of separation between one half of a breeding pair and the other half. Line breeding is a form of inbreeding where you aim for crosses that are made with plants that have around 50% related ancestry.
With orchids this is a long term process due to the length of time between generations. In my opinion, the best thing you can do in a breeding program is to inbreed and see if any bad traits show up. Selfing and sib crosses are the fastest way to see what’s hidden. If Your crosses produce inferior offspring you can get rid of the breeder instead of outcrossing it and spreading a bad hidden trait to a lot of offspring. If you start with good plants that are from selfings and/or sib crosses you’ll be a step or two ahead. One way to do it would be to select offspring from your first cross with the traits you desire and breed them back to the parents. Continue breeding the best of each generation back to those original plants. After a couple generations you can start using ‘cousins’ or ‘aunts’ and ‘uncles’... etc.

 

[My Green Pets]

Phred some brilliant insight there, thank you so much.

I do not know if my first generation were from a selfing, sib cross, or outcross. Because rexes are fairly rare, I suspect they are from a selfing. But as I don't even know where they come from, I don't know how I'd ever know for sure.

The crossing back to the parents is a fascinating point. My strongest and fastest-maturing plants have also proven to be fairly tough, but even some of them have had problems with rot and fungus. I wonder if the parents will be around long enough to see their progeny bloom. This year's pod will definitely be a selfing of my favorite plant, 'Inti'.

 

[tnyr5]

A few more things to consider before line breeding:
- In my opinion, both parents must bring something exceptional to the table, otherwise you're just wasting time waiting for lightning to strike. Reserve selfings for the one-of-a-kind outliers and the magic breeders that turn all their offspring to gold. You need superior traits for which to select. This was touched on by others as well. Be honest with yourself about how good they really are & be unflinching in your standards. There is no room for a parent's love when selecting broodstock.

- You're going to want to raise at least 100 of each generation, and that's after discarding runts and poor performers. That means you'll want to deflask around 300 plants and keep the fastest third, if you're breeding for speed.

- Know the standard and know what already exists. Nothing could be worse than doing 5 generations of line breeding, only to have them easily outclassed by an ex-collected plant. There's very little point in breeding 12cm flowers if someone else is producing ones that are 15, for example.
Which ties into:
- You're doing a Cattleya, and a tough one at that. THIS NEEDS TO BE WORTH 50 YEARS OF YOUR LIFE TO YOU LOL. I'm not really exaggerating. Plan on at least 6 generations before you start to see entire grexes that are consistent.

Personally, I'm with Littlefrog. Find someone with an unrelated plant that's as good or better than yours and make an outcross first. The resulting hybrid vigor will blow anything you can do in the first few generations out of the water.

 

[My Green Pets]

Thanks Tony, I hope to be able to do that in the future. Right now, I just can't do hundreds of seedlings. At the very least I am making lots and lots and lots of this plant available to growers who want to try one.

The AOS awarded clone has been my top choice for sib crosses so far. But the one I intend to self is the toughest, most vigorous, biggest, and most robust of the group. It's going to judging Saturday and I hope its flowers are in prime condition to be awarded something.

 

[ScientistKen]

Great advice Tony. Regarding selfings, there's actually a use to that if you have the space to grow 20 or so. This can give insights into whether a plant has one or two copies of gene. If it's heterozygous for a trait, you should get one or more double recessive plants to tell you that it is heterozygous. This can help pick out superior plants to breed with. Probably most useful for color traits.

 

[Ozpaph]

Im with tnyr5. ONLY breed with the best of the best.

 

[My Green Pets]

I just sent seed to the lab made from crossing the only two awarded Cattleya rex in the US. I hope that qualifies.

 

[Carmella.carey]

Just remember not to breed from siblings, parents and children tooo to much and mix up the gean pool so that you don't have a paph.delenatii incident. If you would like me to elaborate please ask.
Patrick

 

[NYEric]

If you would like me to elaborate please ask.
Patrick

Please do. Knowledge is power.

 

[Carmella.carey]

Please do. Knowledge is power.

Well when delenatii was first brought from Vietnam to Europe most of the plants died and if they didn't die the wouldn't grow well so the almost all the delenatiis in cultivation were bred from selfing one plant and after soo many years of selfing and crossing back to plants that were all from that original plant the lack of fresh individuals depleted the gean pool among this species and all the domestic delenatii were very weak but in modern times most of those old delenatiis aren't being bread any more and we have good, strong, robust and vigorous individuals of delenatii for sale in domestic plants.
Patrick

 

[littlefrog]

The way I heard it was there was only one surviving in France after WW2. They were pretty hard to grow before the new importations added some heterozygosity to the gene pool. Not that that stopped me. Although I did see one in the 90s with 4 flowers on one stem. The grower wouldn't sell me that one... Modern delenatii are extremely vigorous compared to the old ones.

Similar issues with rothschildianum (although I think that was more that people in the US stopped growing them for a few decades), almost everything could be traced back to 'Charles E', 'Mount Milas' and 'Rex'. Pretty sure there was new blood introduced into roths too, and now they are everywhere. I have an old one and a new one blooming right now, they are almost identical but the new breeding bloomed in three years and the old ones used to take 10+. Paph sanderianum is (or was) pretty inbred too, I'm not sure if that has changed. Have one of those blooming now, but the plant does not grow well... Actually a lot of the multifloral species were pretty inbred, they weren't at all popular 30 years ago, too big maybe? Like everything else in paphs, these things go in cycles.

 

[Carmella.carey]

The way I heard it was there was only one surviving in France after WW2. They were pretty hard to grow before the new importations added some heterozygosity to the gene pool. Not that that stopped me. Although I did see one in the 90s with 4 flowers on one stem. The grower wouldn't sell me that one... Modern delenatii are extremely vigorous compared to the old ones.

Similar issues with rothschildianum (although I think that was more that people in the US stopped growing them for a few decades), almost everything could be traced back to 'Charles E', 'Mount Milas' and 'Rex'. Pretty sure there was new blood introduced into roths too, and now they are everywhere. I have an old one and a new one blooming right now, they are almost identical but the new breeding bloomed in three years and the old ones used to take 10+. Paph sanderianum is (or was) pretty inbred too, I'm not sure if that has changed. Have one of those blooming now, but the plant does not grow well... Actually a lot of the multifloral species were pretty inbred, they weren't at all popular 30 years ago, too big maybe? Like everything else in paphs, these things go in cycles.

Thanks!, a bit more information I heard this story from Norman Fang in 2020 all cut off from OS meetings & shows do to the C-Vid I started watching his 45 to 1hour live streams on YouTube that he did on the weekends and was especially excited when he talked about Catts and slippers.
Patrick

 

[ScientistKen]

I agree that maintaining diversity of the gene pool is definitely important, but it does complicate line breeding.

 

[eds]

In many, many species, inbreeding is only an issue if you have deleterious genes in the mix. As stated earlier, start with good plants, select rigourously and you can breed a homozygous population without those negative genes.

A lot of inbreeding depression is suspected to be down to recessive genes being expressed through crossing siblings. Weed those out and you can have a very inbred, strongly growing population. Think of all the album forms in captivity compared to the wild - these will all be recessive genes in the wild population and very rarely expressed in an outcrossing population.

Also, with species collected from the wild, the Founder Effect can lead to a very different gene pool being established in captivity to that of the wild population and that is rarely a good thing.

Each species has a different tolerance to inbreeding and some simply can't take it and need to be regularly outcrossed but it is amazing how inbred even some complex mammals can be and still be very healthy. Other animals (such as humans) cannot even cope with a few generations of inbreeding (as the royal families of Europe proved around the turn of the century).

There are lots of Paphs formed from sibling crosses and many make superb plants. I think the bit that can skew the opinion of line breeding is when runts are kept and sold (due to their worth) instead of being culled. In many line breeding examples of highly selected species (guppies, goldfish) only the very best are kept or sold on and I don't think this always happens with Paphs or, for example, dogs as each plant, even those with negative mutations are worth too much to cull.

 

[My Green Pets]

Had the opportunity to look at the latest seed under a microscope. If those little blobs are alive, it looks like a really solid percentage of viable seed.