I've been growing a particular strain for about 6 years now. Started from one packet of nice European seeds and have just kept replacing the mother plants every 6-8 weeks with one of the cuttings from them. The mums live in a flood system running rockwool with a 400W HPS.

A fellow I know who is much more knowledgeable about botany than I will ever be has said that it's a bad idea to clone off a clone off a clone etc. Something about the aleles(sp?) or other genetic changes over time.

However, a cutting is a straight copy of the donor plant's DNA. Absent any forces that would cause genetic mutation (aside from the fluoro UV ioniser in the room), how would such changes occur?

My experience, at least with this one strain, is that there's no problem at all replacing mums with their 'children' and continuing to feed the flowering area for years and years.

The end-product quality is as good as it was in early days even 6 years on. Whenever I see a change in a batch, I know something's wrong in the environment I'm providing- humidity's off, picked up some bugs, etc.

What's the experience of others who have made copies of copies for a number of years?

There are strains that have been around for years and are only available by clone. They are some of the most sought after plants around. Also, some strains actually improve over time after several clonings. Cindy-99 is one that comes to mind.

Vi

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I agree with Vi
I don't think there is any diminution of the genetic integrity of the original plant....
I have heard growers mention this phenomenon, but have not experienced it first hand....

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Well, I haven't had any noticeable loss of potency, or any other attribute except yield. I would say older plants don't yield as much, and it's because there's a loss of vigor in the growth, so they yield less.

I keep my mothers for about 6-8 months though. So I go through about 2 'generations' per year, while you are changing every other month, so you burn 6 generations per year. At 6 years, and 36 generations, do you notice any loss?

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No, it's all running like it always has. I replace mums very frequently- and that just might be the trick. I don't have any 'old plants' but of course I've been propagating the same strain (Sweet Tooth #4) for these many years.

I have always contended with my botanist mate that every cutting is made of only 2 week-old plant material, so it'd be unlikely that any cells in the plants would be alive long enough to be mutated by any force.

Absent any sexual reproduction in my op, there's no real convenient way to alter the DNA of what I have.

There's an argument that age of the plant is carried along in the genetic protein strand. This argument is supported in the fact that you can start budding clones earlier than similiarly-sized seedlings.

A plant is much more simple genetically than say, a lizard, puppy, or human, so throwing off chromosomes with mutations being just as likely as with other species, it's less tolerable to plants because of their simple genetic structure, and larger relational impact on the total chromosome.

Regardless of the complexity of the genetic structure, there is an inital marked increase in vigor with clones taken off seeded plants vs. that from recursive clones (clones of clones of clones, etc.), and this diminishing-vigor effect becomes more noticable over time (sometime years, depending on strain).

These "much sought after strains", if authentic, can be rather difficult to re-propogate, unless a seeded chromosome is thrown into the mix on occasion.

Simple Mendelian Genetics should be a prerequisite for all growers who don't have instant,verifiable,reliable access to quantity of seeds of known strain.

I should have qualified my previous comment by saying I majored in botany/horticulture/floriculture, and while I haven't studied these issues firsthand, I have had many a discussion about this very issue with those who have. The place I live is a biotech capitol.

Heady, thanks for the info. I see all your points.

Mind you, in this sort of anonymous situation, if you feel the need, perhaps it's better to qualify your suggestions with references to papers or books or links to web resources about the topic rather than trying to qualify your anonymous self.

I'm not actually having any problems with the output- it's like clockwork, same every time as long as the enviro conditions remain the same in the op. However, after approaching 7 years running this DNA, I am sorta wondering if my luck was gonna run out. So far so good, though.

Well from my own expirences and from talking to others on this subject.We all have had the same out come with clones becoming stronger if anything.The clones seem to have a small start off slowly but after 4 or 5 days the speed seems to double and sexing of the plant no longer a need allows you to rip and run having meag fast vegging.Im no botanist but I have been growing a starian that I know is at least 7-8 years old in origin been clone by at least 20 people over and over again and Id say my first clone generation had to be over 200 gens deep and Im on my 10th gen myself and am more then happy with its results everytime..

AL_B

I agree with your points. Out of respect for the anonymity of the authors, I'll simply refer to a good launchpad for those interested in these and other cloning issues. Despite the title, it is actually a very good starter for info on cloning:
The Complete Idiot's Guide to Understanding... - Google Book Search