US Nicotiana Germplasm Collection 2013 Nursery

[Jack in NB]

This thread has to be the most wide-ranging and informative I've encountered in my years of browsing tobacco-related groups.

I'm thoroughly enjoying it!

 

[JessicaNicot]

So would you get better offspring from growing 3 heads of 3 plants the same variety in one big bag then??

if it was already an inbred, pureline, then it shouldnt matter. it'd be the difference between the offspring of one plant or the offspring of basically 3 clones.

 

[JessicaNicot]

If a strain is already considered pure, it would seem that "open pollenation" would be like inviting all the local "junk yard dogs" to your kennel when your best purebred female is in heat.

Unless as Jekylnz said, you could somehow confine your best plants within the same bag with a handful of bees, and hope that they cross pollinate. Not likely.

I would speculate that a quarter million seeds from a single plant should provide plenty of "diversity".

i love your analogy and it is somewhat on point. however, muts do tend to fair better healthwise than inbreeding and good dog breeders will never breed within a bloodline. inbreeding is bad in animals/people primarily because it increases the incidence of recessive genetic disorders.

your last bit is exactly on point. a pureline has no genetic diversity by definition and one plant will suffice for regeneration (unless you notice its a mutant/off type).

 

[JessicaNicot]

i feel like you guys are still missing the most important point. your seeds are already mostly pureline. there is diversity between cultivars (arguably depending on their pedigrees. modern commercial tobacco cultivars are actually one of the most inbred crops.) but the seed of each cultivar is like a bag of clones with each seed identical to the next if the line has been properly maintained. and yes, this is true for all commercial cultivars of all crops (again, because farmers rely on uniformity for production/harvest) and much of the materials in grin.

if you cross 2 cultivars, you'll get what's called f1 seed. if you grow up the f1, all the plants will look generally the same because they are actually a pureline hybrid with half their genome from each parent. if you self pollinate the f1, you'll get f2 seed. when you grow up the f2, given that youve made a wide cross between two very different parents, you'll start to see all sorts of diversity in the progeny that reflect the random assortment of genes and crossing over. the f2 now constitutes a "population" that represents all the diversity present within the parents. what plant breeders generally do is select the plants with the qualities they like best and then self pollinate them. they continue selecting the best of each progeny (for generally 6 or so generations) and then the line is generally considered to be a pureline.

my germplasm collection maintains tobacco diversity by maintaining many different accessions. these accessions came in many different forms, either purelines or open pollinated. however, these accessions have been maintained (some since the 1930s) by strict selfing and thus are generally thought of today as purelines because they have been amplified more than 5 times with a small number of plants. there is basically no genetic diversity remaining within lines, but plenty of diversity between lines that (i hope) represents all that is possible within N. tabacum.

 

[leverhead]

i feel like you guys are still missing the most important point.

I can't speak for anyone else, but I'm very much a "Freshman" to any of this. This has become my favorite thread! Thank you for your patience with us.

 

[FmGrowit]

my germplasm collection maintains tobacco diversity by maintaining many different accessions. these accessions came in many different forms, either purelines or open pollinated. however, these accessions have been maintained (some since the 1930s) by strict selfing and thus are generally thought of today as purelines because they have been amplified more than 5 times with a small number of plants. there is basically no genetic diversity remaining within lines, but plenty of diversity between lines that (i hope) represents all that is possible within N. tabacum.

That's really quite incredible. What an honor it must be to be working with such history. Cheers to you Jenifer

 

[workhorse_01]

I look forward to it each day also. Now I'm thinking of another post where someone wanted to cross two different plants to get a f1. I want to keep my seed pure but with this thread, I'm seeing all the plants we are growing are the result of someone's idea of the best progeny self pollinated many, many, times over and is now considered pure. By Jessica's explanation there should only be a handful of true pure strains, and I'm willing to bet they are the highest nicotine plants.

I can't speak for anyone else, but I'm very much a "Freshman" to any of this. This has become my favorite thread! Thank you for your patience with us.

 

[johnlee1933]

I can't speak for anyone else, but I'm very much a "Freshman" to any of this. This has become my favorite thread! Thank you for your patience with us.

If you're a "freshman" I feel I'm just entering first grade. But it' all good. I'm soaking up as much as I'm able.

 

[NRustica]

i feel like you guys are still missing the most important point. your seeds are already mostly pureline. there is diversity between cultivars (arguably depending on their pedigrees. modern commercial tobacco cultivars are actually one of the most inbred crops.) but the seed of each cultivar is like a bag of clones with each seed identical to the next if the line has been properly maintained. and yes, this is true for all commercial cultivars of all crops (again, because farmers rely on uniformity for production/harvest) and much of the materials in grin.

if you cross 2 cultivars, you'll get what's called f1 seed. if you grow up the f1, all the plants will look generally the same because they are actually a pureline hybrid with half their genome from each parent. if you self pollinate the f1, you'll get f2 seed. when you grow up the f2, given that youve made a wide cross between two very different parents, you'll start to see all sorts of diversity in the progeny that reflect the random assortment of genes and crossing over. the f2 now constitutes a "population" that represents all the diversity present within the parents. what plant breeders generally do is select the plants with the qualities they like best and then self pollinate them. they continue selecting the best of each progeny (for generally 6 or so generations) and then the line is generally considered to be a pureline.

my germplasm collection maintains tobacco diversity by maintaining many different accessions. these accessions came in many different forms, either purelines or open pollinated. however, these accessions have been maintained (some since the 1930s) by strict selfing and thus are generally thought of today as purelines because they have been amplified more than 5 times with a small number of plants. there is basically no genetic diversity remaining within lines, but plenty of diversity between lines that (i hope) represents all that is possible within N. tabacum.

I think that is a great explanation but I have one question, I'm coming at it from a pepper growing background. Usually with peppers if I pollinate 1 Trinidad scorpion to another Trinidad Scorpion it would be considered f1 and if I selfed the TS it would still be f1. Whereas if I crossed the TS with say a Jalapeno then that seed would be considered a hybrid f2. Why the difference? Perhaps it's genetic semantics or I misunderstood what I was told. I understand the whole getting down to a pureline cultivar of what you described.

 

[deluxestogie]

F1 (filial 1) is always the first progeny generation, regardless. F2 is always the second generation; F7 the seventh. If, instead you call it a hybrid, then it further defines it as an F1 hybrid...F7 hybrid.

Bob

 

[JessicaNicot]

I look forward to it each day also. Now I'm thinking of another post where someone wanted to cross two different plants to get a f1. I want to keep my seed pure but with this thread, I'm seeing all the plants we are growing are the result of someone's idea of the best progeny self pollinated many, many, times over and is now considered pure. By Jessica's explanation there should only be a handful of true pure strains, and I'm willing to bet they are the highest nicotine plants.

i cannot vouch for high nicotine content being the "ideal". modern commercial cultivars (tn 90, k326, etc) had to meet the minimum standards programs and thus were required to fall within a certain range of nicotine and other chemical traits, however older cultivars (like many of the ones im growing this year) did not so you might be able to find a high nicotine gem in there. but if high nicotine is your goal, N. rustica is your ticket, hands down. there once was a high nicotine line (i think it was called y1, but dont quote me on that) that was a high nicotine line derived from a hybridization with rustica. yeah... so when the gov crackdown on tobacco started, that seed line (which used to be in the collection back in the day and was developed at the station in oxford) and all the info relating to it vanished...

this is my PSA regarding this topic: let's not forget nicotine IS a DRUG and large doses can kill you. i dont smoke so i have no tolerance and when i've handled a lot of tobacco (and not remembered to periodically wash off the grime) i've gotten pretty sick.

 

[JessicaNicot]

F1 (filial 1) is always the first progeny generation, regardless. F2 is always the second generation; F7 the seventh. If, instead you call it a hybrid, then it further defines it as an F1 hybrid...F7 hybrid.

Bob

there are lots of complicated notations for generations and writing pedigrees. you might see BC1F1, which means the progeny resulting from taking an F1 plant and crossing it back to one of the parents of the original cross. some people use S instead of F. in gmo work they use T. even after taking a course in plant breeding it can still take a bit of mental effort to work thru some of these notations. BC5F2 means you made an original cross, serially backcrossed the progeny 5 times to the recurrent parent, and then selfed it once. in corn they tend to do a lot of crazy crosses and you may see 3 and 4 way crosses combined with backcrossing and then selfing.

 

[JessicaNicot]

I think that is a great explanation but I have one question, I'm coming at it from a pepper growing background. Usually with peppers if I pollinate 1 Trinidad scorpion to another Trinidad Scorpion it would be considered f1 and if I selfed the TS it would still be f1. Whereas if I crossed the TS with say a Jalapeno then that seed would be considered a hybrid f2. Why the difference? Perhaps it's genetic semantics or I misunderstood what I was told. I understand the whole getting down to a pureline cultivar of what you described.

i dont know a lot about peppers, but if you made an F1 and then crossed it to anything other than one of the parents it would be considered a 3 way cross (or a 4 way cross if you crossed it by another F1 with 2 different parents). if you self an F1 the resulting progeny will always be the F2, and so on as Bob explained.

 

[NRustica]

Thanks. I stand corrected.

 

[workhorse_01]

No it isnt my goal, but my thought process was that when the crossbreeding began that the nicotine content was cut in half at the f1 level then cut some more at the f2 level by the time we got to the progeny level there's no telling where the nicotine level would be. Personally what i'd like is a moist snuff that gives a good nicotine hit with a smokey flavor, that i dont need a surgeon general's warning on.

i cannot vouch for high nicotine content being the "ideal". modern commercial cultivars (tn 90, k326, etc) had to meet the minimum standards programs and thus were required to fall within a certain range of nicotine and other chemical traits, however older cultivars (like many of the ones im growing this year) did not so you might be able to find a high nicotine gem in there. but if high nicotine is your goal, N. rustica is your ticket, hands down. there once was a high nicotine line (i think it was called y1, but dont quote me on that) that was a high nicotine line derived from a hybridization with rustica. yeah... so when the gov crackdown on tobacco started, that seed line (which used to be in the collection back in the day and was developed at the station in oxford) and all the info relating to it vanished...

this is my PSA regarding this topic: let's not forget nicotine IS a DRUG and large doses can kill you. i dont smoke so i have no tolerance and when i've handled a lot of tobacco (and not remembered to periodically wash off the grime) i've gotten pretty sick.

 

[workhorse_01]

But can the f8 be considered a pure line as far as clones by self polination? Or at least i think thats what she was explaining.

F1 (filial 1) is always the first progeny generation, regardless. F2 is always the second generation; F7 the seventh. If, instead you call it a hybrid, then it further defines it as an F1 hybrid...F7 hybrid.

Bob

 

[deluxestogie]

The generations are simply numbered from whatever starting point you chose. If it's always selfed, then it's still a pure strain. The generation numbers (f1, f2, etc.) have more significance when they are based on a cross, since dominant and recessive traits are revealed in different proportions in different generations.

Here are a couple of straightforward explanations (non-technical)
http://anthro.palomar.edu/mendel/mendel_1.htm
http://ed.ted.com/lessons/how-mende...us-understand-genetics-hortensia-jimenez-diaz [video]

It all gets pretty messy at the molecular level, especially with tobacco, since it originated when all the chromosomes of two different Nicotiana species were slammed together (by Mother Nature). So, tobacco--Nicotiana tabacum--ended up with gobs of extra genes--nearly everything from each parent species--resulting in many duplications.

Bob

 

[workhorse_01]

Thank you for the links.

The generations are simply numbered from whatever starting point you chose. If it's always selfed, then it's still a pure strain. The generation numbers (f1, f2, etc.) have more significance when they are based on a cross, since dominant and recessive traits are revealed in different proportions in different generations.

Here are a couple of straightforward explanations (non-technical)
http://anthro.palomar.edu/mendel/mendel_1.htm
http://ed.ted.com/lessons/how-mende...us-understand-genetics-hortensia-jimenez-diaz [video]

It all gets pretty messy at the molecular level, especially with tobacco, since it originated when all the chromosomes of two different Nicotiana species were slammed together (by Mother Nature). So, tobacco--Nicotiana tabacum--ended up with gobs of extra genes--nearly everything from each parent species--resulting in many duplications.

Bob

 

[skychaser]

I've been too busy and too tired to spend any time at the computer the past couple days so I am just getting caught up here.

Does the FTT seed bank do multiple seed grow outs of the same variety seed, to combine the seed after from different parts of the US.? It seems to me that would give us the highest seed viability.

Since the quality control of seed production varies from one grower to the next, I would not be in favor of combining them into a single tub, nor of combining seed from the same grower produced in different years. Seed should be separated by grower and year produced.

Actually, I think you both are right. Combining seed from different grows is recommended by many seed savers. It does increase the genitic diversity and thus the overall viability. Growing and combining seed from two successive years from the same original seed stock also increases diversity and viability. If you have a rare type of seed, or a limitied number of seeds, this is the method recommended by the Seed Savers Exchange.
But.....as Bob said, the seed is only as good as the people growing it. If you are certain all parties involved are adhearing to the same standards of quality control, and you all have a good trustable seed stock to start with, then it is sound method. If not, forget it.

corn is a terrible example to use for seeing inbreeding depression effects when you save seed year to year because all the commercial seeds are Hybrid.

Not true. None of the corn I grow is a hybrid. In the corn fields of Iowa, yes, you will find only hybrids. Hybrids probably make up 80-90% of Americas corn production today. But on small farms. organic farms and in the gardens of America, you still find a lots of heirlooms. Home growers are running away from hybrids in droves these days thanks to that wonderful company called Monsanto and their BT corn. Hybrid is becoming a dirty word to the ill informed and being associated incorrectly with GMO crops. Hybrid sweet corn is delicious. With a sugar content as high as 40%, how could it not be? It's practically candy. lol And about as nutritious when compared to heirlooms and Dent Corns. Heirloom corn is actually an excellent example of what can happen with inbreeding depression. But corn is a wind pollinated grass and it is miles away from tobacco, so I will agree it is irrelevant to this discussion. I brought it up only as a most extreme example.

Jessica, I find this discussion most interesting and I hope I am not coming across as being antagonistic. That is not my intent. I appreciate your presence here. What I am really hoping is that you can convince me that I do not need to grow as many plants as I do, and I will still retain all the characteristics of a strain and the highest possible level of quality in my tobacco seed. I would love to accomplish the same results with half the work. My back hurts a lot these days. :/

Sky

 

[JessicaNicot]

But can the f8 be considered a pure line as far as clones by self polination? Or at least i think thats what she was explaining.

somewhere i have a list that shows that with each round of selfing on an F1, the percentage of ****zygosity in the genome. i'll try to find it for you guys. its been too long since i took the class to recall the theories used in order to calculate it out myself, but it is a widely known set of stats amongst plant breeders.