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Willamette Valley, Oregon

"Generation Time" is the average time between two consecutive generations in the lineages of a population.
-wikipedia

Every successive generation of selection should lead to an advancement in the trait(s) being selected for. So a lower generation time (assuming similar selection pressure) in each generation should be beneficial.

The average generation time for 2017-grown pumpkins was ~1.7 years. That is, the average seed is from 2015.3. So in a 10 year period there would be 6 generations.

However, if the generation time was lowered to 1 year (which is easily done, by just growing the most promising new seeds each year), there would be 10 generations in a 10 year interval; 4 more chances to make selections!

If we assume a 4% gain per generation via current selection procedures, and a starting point of 2000 lbs, in 10 years the weight would be (hypothetically) :

status quo (1.7 year / generation): 2530 lbs
new seeds only (1 year / generation): 2960 lbs

Some folks might think that the selection would be better with proven seeds (I'm skeptical of that), but assuming that's a possibility let's put some numbers to it:

In order for "status quo" to equal the effectiveness of "new seeds only", the "status quo" selection would have to yield 5% gain per generation, while "new seeds only" would gain 3% per generation (yielding 2700lbs for each). That would mean that the selection benefit in "status quo" would have to be almost 2x as good just to break even. I'd be amazed if that's true.

12/27/2017 7:04:20 PM

Bloomington, IN USA

What are you assuming for numbers for selection?
That’s a big factor and having world class growers doing it would be vital.
What about enlisting Southern Hemisphere growers in the loop...gives you 2 generations per year?

12/27/2017 11:52:35 PM

Willamette Valley, Oregon

Implicitly it assumes a typical year of ~1500-2000 fruit, but the actual number of plants grown isn't a consideration directly in this calculation.

I used 4% gain per generation because that's approximately the gain we actually see generation over generation in the GPC data. (GPC data shows ~2.3% gain per year with an average of ~0.6 generations per year = ~4% gain per generation).

I do like the S. Hemisphere idea, but we'd really need a lot more growers down there for the selections to be strong enough. And we'd need to harvest our seeds and get them down there faster.

12/28/2017 11:59:26 AM

Grittyville, WA

You have some awesome ideas ... Love your ideas...

12/30/2017 8:20:52 PM