Re: Hybrid Vigor
Michael:
I agree with everything you said, but don't count out mutations; hidden
genetic tendencies; the effects of environment & culture, & genetic nicking. I
really believe that genetic selection for size will keep improving size. Hybrid
vigor does not always result in vigor in the area you are striving for, & could
just result in hardier, stronger vines; or thicker tougher stalks or thicker
rinds, etc., because these factors , too are present in both varieties.
I think that hybrid vigor is sort of like enhanced good luck. i.e. you know
you're going to get something good (probably better than both parents); but I
wouldn't count on size being the only option. In addition, here's where the
nicking factor comes in. A nick is frequently described as a "golden cross".
The two families, consistently crossed, provide repeated, uniform hybrid vigor
& improvement. Any two families selected at random for specific variation, will
not necessarily produce the hybrid vigor you are looking for. In Arabian
horses, this cross was exemplified by the Raffles - Rissalix cross. The Raffles
horses were smaller, very pretty, sturdy, & basically correct. The Rissalix
horses were the "action" horses: those with tremendous movement & athletic
ability. They were taller, reachier, flashier, & higher tempered, etc. When
crossed, those two lines consistently produced outstanding stock, that won both
for conformation & performance. Each was the other's best cross. As long as you
used good quality individuals from each line, success was virtually assured.
This is what a "golden cross" or "nick" is.
Carrying this "nick" forward, or attempting to establish your own
(successful) hybrid cross is not as easy; since you must locate & establish the
right lines for the most consistently successful matings.
As an example: in horses, Secretariat was "the stallion" to breed to for
Thoroughbred race horses. Yet, he never lived up to his potential. He was
perhaps technically a hybrid, himself, being by a speed family out of a
distance family. But none of the initial offspring achieved a whole lot (as far
as becoming major or champion racers). Then there were a few good ones (really
nice stakes horses) in the next couple of crops. Then, later, there were
several champions, & quite a few good race horses.
The secret that provided the change in quality of offspring? The mares he
was mated with. Since he was so great himself, they mated him to the best in
the world. Since speed is hereditary, they figured that even if he improved the
genetic quality of the mares a few seconds. the foals would all be top class
race horses, probably many of them champions. Instead, they got some nice
horses that never achieved anywhere near the heritage of either family.
There were 2 deciding factors here. First of all, one of the main industry
opinions is that the mares were too good for the cross. they were approximately
his equal, & there was nowhere to go ( they were already as good as it got).
This could have been born out by the fact that when bred to the second level
mares, later in his career, his statistics of speed & quality in his offspring
improved tremendously. The idea in this theory is that the second level mares
were not in his speed category, so he could throw improved speed & stamina onto
their genetic heritage.
The factor that is probably far more near the truth is environment &
culture. The first foals of this stallion were viewed as "whiz kids". they were
pampered, trained with care, & entered into the big races. It didn't work. Why?
One very good theory states that they inherited the slower maturity of his
dam's lines, & that they did not attain their mature speed or stamina in time
for the early races they were entered in. By the time they would have attained
them, the owners had given up & weren't racing them any more. The later horses
were trained more slowly, in many cases, but this was due to economic factors,
too. Since he had not done that well as a sire, his stud fee dropped. Since the
breeders did not have as much invested in the foals, they could afford to take
their time & wait a bit.
Another factor is that during the latter half of his career, tremendous
strides were made in the areas of feed & nutrition. These would have been
applied to the offspring, & would certainly have had a beneficial effect upon
their development & potential.
The point of all this is that it took a bit of everything to develop the
better offspring. The best genetic heritage (hybrid vigor, or genetic selection
for traits) is only as good as the environment & culture available to it. I
will point out that the diverse sizes in the same pumpkin crops, (even those
now down several generations of genetic development for size) somewhat bears
out this theory.
Michael is right, but don't let him make the selection sound too easy. If
it were, a lot more of us would have giant pumpkins. I recommend you select the
best seed you can get, & try to furnish the rest of the improvement from
environment & culture. If you study the notes on this list, you will note that
whether small or big plot, the largest pumpkins are usually grown with
necessary shade; plenty of water, proper root development; good soil
conditions, & regular fertilizing. This kind of culture can make up for a lot
of heritage in a pumpkin's development. While it won't make a miniature pumpkin
(by heritage) into a giant, it would certainly help turn what might be a 2-300#
pumpkin into a 5-800# or larger. & It clearly already has.
TerryLynn
