G'day PvR,
[Except for that lowercase "v" we could be speaking Plant Varietal
Rights. :-) ]

In article , "P van
Rijckevorsel" wrote:

"P van Rijckevorsel" wrote:
[snip]
To clarify an example. An "odd and isolated fact" would be that peas are
self-pollinated as you note. An odd fact interwoven with other facts to make
up an interesting whole is that Coffea arabica is also self-pollinated,
which means that as a result it is easy to get seed that is homozygous for
many properties. As a result of that it is possible to have coffee-strains
with desirable properties which can be propagated by seed, which is rather
unusual for a cultivar (there are many people who think cultivars must be
propagated asexually, with only some people aware of F1-seed hybrids.
Propagation of cultivars by seed, generation after generation, is discounted
as an impossibility by most people). Of course these homozygous strains of
Coffea arabica are very vulnerable to diseases: hence the famous plagues in
this crop.
[snip]


Phred wrote
Many cultivars of pasture grasses and legumes are propagated by seed
for a number of generations -- but perhaps not as long as your
"generation after generation". :-)
Cheers, Phred.

+ + +

Just out of curiosity, the point came up that almost all self-pollinated
cultivars were annuals: I assume pasture grasses are perennial? And perhaps
legumes too? Although I have an image of many legumes being used as an
annual crop, being plowed under at the end of the year.
PvR

Amazing! I meant to add to that snippet, but never got round to it;
and the other night I mistakenly must have hit "Yes" to my
newsreader's routine question about sending pending items in the
outbox -- and a whole thread seem to redevelop. :-)

Yes, most (all?) tropical pasture grasses that I'm aware of are
perennial -- but then many (most?) are also apomictic, so the question
of selfing/outcrossing does not arise.

WRT the legumes, all the most successful ones for permanent pastures
are perennial. Many (most?) are self-pollinating and a lot of them
are cleistogamous; but others are usually considered to be outcrossing
(e.g. probably _Desmanthus_ spp. and the important browse plant
_Leucaena leucocephala_.) Some were thought to be essentially
self-pollinating [and most likely usually are] but do seem to have
some outcrossing [or, some cynics might claim -- mixing ;-) ] leading
to a fairly variable "cultivar" these days (e.g. current generations
of _Stylosanthes scabra_ cv. Seca from at least some seed merchants).
But this is seen to be a Good Thing, so no one is concerned.

Most seed production of the tropicals in Oz is done commercially
without "official" supervision. Though there is provision for growing
"certified seed" under inspection if required, it's hardly used in the
tropicals these days AFAIK.

The main outcrossing legume I can think of offhand is lucerne
(_Medicago sativa_ -- alfalfa to you yanks) and cultivars of this
certainly used to be propagated here as open pollinated varieties.
They probably still are, though I can't be sure about the modern ones
developed to overcome lucerne mite and sundry diseases etc.

You are correct about annual legumes being used as cover or green
manure crops etc. I think annuals are preferred for this sort of
application because, in general, they have larger seeds and hence
better early vigour -- so you get better weed control and a decent
stand that's worth ploughing in in the first growing season.


Cheers, Phred.

--
LID