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Select or Open Pollination to make F2's?

B

Bass Akwards

Member
Use several males ...

Use several males ...

Back in the day, Vic High published a short guide to stabilizing an F-1 cross.
It was his simplified version of RRS, and uses multiple males. It's certain to be archived in several places online. Search under BCGA.

It's all well and good to use one male that displays trichomes, but they're few and far between, and almost never show up unless hundreds of sprouts are grown out. It's much simpler, and better breeding practice in the long run, to eliminate several males from a population, and use several others, than to pick out just one of them to use as a pollen source.

Here's a suggested standard for Male Inclusion: Go for the middle.

Several online commentators have stated that the first few males, the ones that are the earliest, fastest growers, have a genetic leaning towards hemp. Others have pointed out that the last males to show their sex have a propensity towards recessive traits.

If both of those notions are true, it's an opportunity to kill two birds with one stone. Out of 15 males, ( a reasonable number if 30 - 40 seeds are started ) eliminate the first and last few plants to grow sacks, and use the pollen of the four or five best looking, strongest smelling, and most vigorous plants in the middle of the pack.

RRS is a "line breeding" scheme that does not depend on back-crossing to achieve stable results. All it takes is time. Unfortunately, with most hobby growers, time and patience are in very short supply.
 
C

Cuzin_Dave

Active member
The problem with using only one male is two fold. All subsequent generations will be bottlenecked because of the small Ne or effective breeding population. The second consideration is what is known as sampling error. In other words there is a potential for the elimination of valuable alleles merely by chance and the smaller the Ne the greater the probablility of this happening.
 
Chimera

Chimera

Genetic Resource Management
Veteran
Pig Pen
"Since F2's typically express all traits of a particular genetic set, recessive and dominant, throughout a large enough population is there any real advantage to selecting a specific male/female pair to make the F2's?"
Click to expand...

>> The clear advantage in creating a population that expresses the complete range of genetic possibilities, in fact the ONLY way to ensure the complete range of genetic possibilities that come from the original hybrid of the parental populations (ie P1 and P2) is to do a open pollination of at least 30 individuals from the F1 hybrid generation.

Selecting individual plants, both male and female, from the initial F1 population and subsequently performing cross-pollinations will produce "F2 families" which may be better, or worse, in some respects compared to the open pollination of the full F1 population. These F2 families may express some specific traits to a higher or lesser degree, but will not contain the full range of genetic possibilities from an open pollinated F1 population.

To summarize, the open pollinated F1 does more to preserve the original genetics of the P1 and P2 populations and the subsequent possibilities that arise from the hybrid cross, and the following F2 generation beyond.

F2 populations derived from selected male and female plants may be more of use in searching for specific traits, as selection pressure on the F1 generation may have started to narrow the pool in favour of traits deemed favourable to the breeder. By corollary, the breeder may have permanently exluded traits that are missed in later generations.

To get the best of both worlds, make an initial open pollenation of all plants to preserve all the alleles of the original P1 and P2 populations, then create F2 families of the chosen individuals after the fact from clones taken from the F1.

I know, seems like a lot of work.... but real breeding is.

-Chimera
 
C

Cuzin_Dave

Active member
At F2 there will be a percentage of specimens with much higher relative fitness than either of the F1 parents. To use Chimmy's example of 30 plants one must remember that that the effective breeding population will always be smaller than the total population.
Ne = 4 * (# of Males) * (# of Females) / (# of Males) + (# of Females)
A number like 30 plants will at least give a partial though somewhat incomplete snapshot of what a line is like. The more F2's that can be run the better.
 
Chimera

Chimera

Genetic Resource Management
Veteran
The F1 N of 30, as stated in my previous post, was indicated to represent the number of plants required statistically to capture to total alellelic pool of the respected P1 and P2 populations of a single cross 1:1 as most of today's cannabis 'varieties' are. As always, the more plants used in an open pollination scenario, better chance of capturing the full allelic set. N= 30 is certainly adequate.

The F2 N required to reveal the full phenotypic expression of the P1 and P2 pools is obviously much higher, but I don't know of anyone from these boards capable of growing on the scale required to do so.

Hope that cllarifies for any doubters.

-Chimera
 
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C

Cuzin_Dave

Active member
Chimmy, you are correct about catching the bulk of the phenotype population distributions. It really is all about finding a good representative sample and building and improving upon the line.
At F2 a person should be able to find patterns among the different phenotypes when Ne equals 30. Not great, but the plant is illegal and the government does not care if people have well bred weed.
 
B

Bass Akwards

Member
On the other hand ...

On the other hand ...

Chimera said:
F2 populations derived from selected male and female plants may be more of use in searching for specific traits, as selection pressure on the F1 generation may have started to narrow the pool in favour of traits deemed favourable to the breeder.
-Chimera
Click to expand...

This seems to explain some of what has happened in the seed business. All the selection pressure in favor of potent plants over the past few decades has evidently made it hard to grow a sensi plant that won't get you stoned. The buzz has become a given. What has changed is the taste, color, and aroma. Selecting for specific traits, like a particular color or smell, isn't that difficult. It takes just three or four generations to create a "strain".

It's much more difficult to find a plant with significantly higher THC/CBD levels than it is to find a plant that smells like oil, pineapple, or lemon. It's even harder to find a higher THC plant that isn't lower in size & yield. You want a big, strong, plant that isn't "fussy"? Good luck.

By todays standards, the "trailblazing" breeders of yore were glorified closet hacks that used small numbers of parents and questionable tactics. Vic High & The Brothers Grimm produced lines that have been become "classics", but Vic never claimed to have grown out large numbers of seeds, and Grimms "cubing" of glorified bag-seed was pure guesswork.

It's doubtfull that Vic used more than a few packs of seeds to select some parents. Several of his female seed parents were clones to begin with. He did lay out a detailed RRS scheme that could be done in a small grow-op, but he never claimed to have used that method himself.

Could it be that the reason that C-99 is so revered as a crossing partner is because it is so very uniform and "bottlenecked"? Its' options are very limited, so the results of a cross using it don't show many variations.
Growing F-3's of one of the BCGA crosses has repeatedly shown large differences in smell & taste, but very few physical differences.

Chimera said:
I know, seems like a lot of work.... but real breeding is.
-Chimera
Click to expand...

So true ...
 
suzycremecheese

suzycremecheese

Active member
xyz said:
well if the hybrid is a true f1(indica/sativa - 50/50) than it's really not important which plants will you use for making f2
rather study how to select the f2(first you need an idea about your wishes -so what traits are you actually lookin for:)
Click to expand...

XYZ makes a great point that I want to elaborate on. Very few F1s are true F1s. A true F1 should be a cross of two unrelated IBLs. Both these lines should have different alleles at almost every,if not every, locus. Then you will truly see the range of possibilities in the F2.

Now if you had a true F1 then both the male and the female would be almost genetically identical in every way but the sex linked traits. So you could get away with using only one of each.

Since most F1s are not true F1s though I believe open pollination is the way to go. Use every healthy male and female that makes it to sexual maturity and try to make sure that every male gets an equal shot at every female. Tough work I know.

Ne = 4 * (# of Males) * (# of Females) / (# of Males) + (# of Females)
Click to expand...

Now if you really think about this equation that cuzin Dave has posted it shows you how much is lost when seed makers use only one male. Plug the #1 into the male slot on that equation and use any number you like for the females. Try it a few times and you see that you could be losing a great deal of those females genes by not using more males.

For example if you use 1 male and 1000 females 1001 total plants...
effective breeding population = (4x1x1000)/ 1001= 3.99

But if you use only 5 males and 5 females...
Ne= (4x5x5)/ 10= 10

You get so much more out of a population when you try to use an equal number of males and females. 1001 plants with a poor male to female ratio has an Ne of less than 4 while a population of only 10 plants at a 1:1 ratio actually has an Ne = to the real population.

Hope that simplifies for someone that might not be grasping it yet.
 
Pig-Pen

Pig-Pen

Member
Whoa. I totally forgot about this thread! :kos:

Thanks to all the contributors. There's lots of good info in here. :headbange
 
wotamess

wotamess

Active member
great thread.

in my first attempt at a seed run, i grew out 10 of a first generation cross of uk cheese pollinated by a leb 27, hence a 'true f1', i.e. two ibl's. i got 3 males and 4 females. one of the ladies was a midget, so 3 viable females (not that i have anything against midgets). the males were left for as long as possible until the main contender staked his claim... best structure and odour. i chucked the other 2 males, and cut the top off the favoured one, and popped it in a bottle of water to ripen up with the ladies. i dusted them, and few others (sensi star cut, biddy's sister, and cheese x danish passion) and ended up with about 400 - 500 seeds... mainly cheese/leb. this was all done under a skylight during the uk summer...

so, i'm at f2, right? should i be happy with the cross? i'm STOKED with my seeds, and was very happy with the smoke from the seed bud. did i limit it by using a single male? will the three females ensure some variety? or does the inbred nature of the parent plants make the project a success?

thanks for the bent ears...

-wam-


 
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B

Bass Akwards

Member
Lots of Testing Required

Lots of Testing Required

Using one particular male isn't so much of a problem in this case since you have multiple females of different varieties.

In most cases, we would classify this as "closet hack" work, but that's OK.

Enjoy the results. It's a fine feeling, making seeds.

Testing each group of plants is next.

Then, you can do an A/B test with two of your favorite versions.

Grow out at least 20 seeds of each cross, and use the all the males of A to fertilize the all females of B, and vice versa. Then grow out those seeds and see which cross worked "best". Do the same with the other three crosses.

Cross every possible combination, select the winners, and cross again.

Carefully compare the results. Keeping good records is mandatory.

When you have evaluated all the possible A/B combinations, go back to the original seeds that you made, and begin again using the best combinations you've found.

Those 4 - 5 hundred seeds, and their spawn, should last you through decades of test grows.
 
wotamess

wotamess

Active member
Bass Akwards said:
In most cases, we would classify this as "closet hack" work, but that's OK.
Click to expand...

jeez, rub it in!! i'm quite aware i've chucked some pollen, bud...

-wam-
 
hoosierdaddy

hoosierdaddy

Active member
ICMag Donor
Veteran
I wouldn't take offense, wota. Unless a person is prepared to do what Chimera and others have suggested, and use a selection of at least 30 individuals, we are all pollen chucking hacks.

I think it's obvious that using a lower number of males for a pollination is going to cut down on the chances of every trait being passed on. And a good point was made by charliex about the numbers that most of us will encounter. Which plays back to the using at least 30 individuals, if you are going to be breeding properly for a true F2 selection.

IMO, picking a male with what you want, and pollinating a female that has what you want, and then search through the progeny for a keeper, is about as far as most of us need to go. And I highly doubt an initial open pollination is going to net you much more to select from than a selected pollination. Especially if using IBL's.
 
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Hindu Killer

Hindu Killer

Active member
Veteran
Ive got some GCxPTK and PI x PTK F2's I will be running this season OD. Plan is to hunt down some GC leaning matureing,smelling males and bx to the GC. The PI the same...


Didnt know XYZ done the SDxPTK....from what Ive read..the SD isnt that stable...like PTK for instance. PTK is a lovely plant and great breeder.

Any thoughts on my project are most appreciated.
 
L

Late_Night_Toke

New member
When you think you can cross any 2 f1s and get all the possible code within the 2 lines like that you might as well be expecting the guy that works at CVS to be the arbiter of medical science, he may represent the subject in some way, but he does not contain all of its essentials, not enought to teach with expertise.

you will get what you put in, why would you get something you didnt put in?

F2s dont give you all possible combinations, they give you the possibility of all possible combinations depending on what they are the sum of.
 
BENJI

BENJI

Between the Devil and the deep blue sea...
ICMag Donor
Veteran
This is an interesting thread i have a question about phenos how much variation in the male side do u get and are there certain male phenos to look out for in any particular strains??
 
B

Bass Akwards

Member
Male Markers

Male Markers

BENJI said:
... how much variation in the male side do u get and are there certain male phenos to look out for in any particular strains??
Click to expand...

The order in which males display their sex is one way to begin tracking them. When working with sufficient populations, the differences become quite apparent. Quite often, what first appear to be the tallest, most vigorous plants end up being males, and these are also inclined to show sex early. They rarely have a pungent odor, and most probably lean towards the "hemp" side of the gene-pool. The last few males to declare have their own possible problems ... they might carry recessive traits, like "hermi-osis".

Out of 15 - 20 males, perhaps half will fall between those two poles. If you're blessed, there will be 5 - 7 with short internodes and a distinct smell when rubbed or handled. By the time these are 18 - 20 inches tall, and in 1 - 2 gallon pots, they can be placed against a white wall with a series of 4 double tube 40 Watt shop-lights leaning over them. That's all that's needed to harvest a load of pollen, over a couple of weeks. Mix each batch, store separately, and use it carry on the line or do a few, judicious, back-crosses.

( Or even a cheap & easy version of the oft-lambasted "cubing" program. )

Shop-lights won't grow much bud, but it certainly works to produce pollen.
 
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