Dear Nita,

In my experience (with succulent plants only), that is true and isn't true.

Aloe pups grown on their own show no difference in vigor and form than those grown from seeds.

Many caudiciform plants (grown for their raised roots "caudex>) will not form caudexes if grown from cuttings - some will, but most won't.

Cacti grown from cuttings, in proper culture, show no difference in growth rate friom that of seed-grwon plants.

I was going to say that neither gentically nor physiologically I can't see why a cutting would be less vigourous but Jeffrey's comment about caudexes (caudices?caudexes?) made me think of the taproot. The taproot grows originally from the embryo. Cuttings do not grow taproots since they don't come from seed and therefore didn't have an embryo. Taproots are roots that go deep in to the soil for water and nutrient uptake.
Cuttings on the other hand have a more adventitious and fibrous root system which is not as 'heavy duty' as the taproot, not do they travel deep into the soil as a taproot would. Perhaps during drought , plants having a taproot (those that came from seed) would be advantaged?

...Cuttings do not grow taproots since they don't come from seed and therefore didn't have an embryo...."
Huh???
Jeffery's comments are specific to caudiciform plants-not necessarily to others.

..."Perhaps during drought , plants having a taproot (those that came from seed) would be advantaged?"

Not at all. I will give you an example; Blue grama grass (Bouteloua gracilis) has a very fiberous root system. It is also a superb and efficient water user. It can make use of minute amounts of water to survive-less than 10th of an inch of moisture.

Perhaps I got a bit caried away and here's a better explanation ; what I mean by 'cuttings don,t have a taproot.... they didnt have an embryo' is that they do not come from seed ; their "mamma" comes from seed. The cutting grows adventitious roots and will never grow a primary root as a plant that comes from seed. Taproots are primary roots.

I know Jeff's (may I?) comment is about caudexes ; correct me if I am wrong but caudexes are (stem) tissue that arise from the embryonic stage. I am curious to know which species are able to grow caudexes when propagated from cuttings? And is the caudex structurally/functionally the same as a seed-grown plant?

For the last comment : I am sure there are lots of plants that do pretty fine with fibrous root systems (many desert plants including (all?many?most?) cacti have very shallow root systems, just to capture real quick whatever moisture comes from above). I am not comparing between different species but comparing a cutting-grown plant to its seed-grown counterpart. I was also talking about a plant that has a taproot vs. one that doesn't because it came from a cutting. In your case, Bouteloua gracilis does not have a taproot, and I am not sure it can be propagated by cutting?
(or can it?).
Naz

Ahhhhh
you are saying that that a cutting will never have the primary since it did not come from seed. Not that a cutting will never grow a taproot. Got it.

errrrrr to me a taproot IS from embryonic origin and therefore primary.
The cutting will grow roots but they are called adventitious roots, not taproot :)

It is the theory of hybrids.

As a general rule, if you have two inbred strains and you hyrbidize them, you introduce vigor into the gene pool. The result is that offspring will have improved properties than both of it's parents (1+1 equals more than two).

However, if you have a well functioning plant created for example by hybridizing with some really unique traits (flower color, leaf color, etc) then cutting will produce identially nice plants (clones).

Seed growing these plants may not re-produce these same desireable traits and so therefore some plants, pelargonium (geraniums) for example are typical examples.

Cutting grown geraniums will typically have larger flower heads, better flowering, deeper foliage zones, etc then their seed grown counter parts. The explanation is that the growers have been unable to refine the seed strain to produce reliably consistent F1 seeds. So the only way to continue growing the specific plants are through cutting.

More details are available in this article:
http://www.suite101.com/article.cfm/18505/109460

Here is a link that might be useful: Understanding Hybrids

Ok now i am confused as to what you are saying.

Are you saying that a cutting from a plant that naturally forms a taproot when grown from a seed will never, ever produce a taproot no mater what its genetic programming is and no matter how big the cutting ultimately gets and these roots that did not come from a seed are properly called adventitious roots???

I think one or both of us are confusing definitions???

Here's a link that may be helpful

Here is a link that might be useful: Roots