Breeding crops for traits - how fast?

[Hans de Vries]

How fast can crops be bred for certain traits assuming we start with wild plants?

Can 1% increse in average mass or speed of growth per decade be achieved if there are 10,000s or 100,000 of people breeding that crop and it is annual?

[Peterkin]

2 hours ago, Hans de Vries said:

How fast can crops be bred for certain traits assuming we start with wild plants?

Can 1% increse in average mass or speed of growth per decade be achieved if there are 10,000s or 100,000 of people breeding that crop and it is annual?

That's not how it works. In ancient times, there were only a few people, scattered around the world, out of communication with one another, discarding the seeds of their food plants around their habitations, then planting the seeds deliberately, then choosing the seeds from the better plants and discarding the less desirable ones, then systematically saving seed from domestic food crops . C. 30,000 years, give or take a few millennia.

In modern times, nobody starts from a wild plant, and food crops are more likely to be gene-spliced than bred for desired characteristics.

In between, from +/-6000BC to the late 20th century AD, deliberate selective breeding might take anything from two generations to produce a reliable round-seeded hybrid (in most cases, this will not breed true, or not breed at all) to 10 generations to breed out susceptibility to a particular disease. It all depends on the characteristic you're trying to fix and what other genes are associated with that characteristic.

[swansont]

5 hours ago, Hans de Vries said:

How fast can crops be bred for certain traits assuming we start with wild plants?

Can 1% increse in average mass or speed of growth per decade be achieved if there are 10,000s or 100,000 of people breeding that crop and it is annual?

I suggest you look at Mendel's experiment with peas. It was only a few generations to identify certain traits (including color and texture, IIRC) but when he moved on to something else he was stymied, because the genetics was more complicated. In peas the different traits are associated with single genes rather than combinations, and there was no "crossover" between the genes and multiple traits. (i.e. genes for x correlate to trait x, y with Y, and z with Z, but these are independent of each other. Not true in all subjects)

So I imagine the answer is that it is going to depend on what crop.  

[Hans de Vries]

Let's say you start with something simple like dandelions.

You want dandelions that are 2x larger than normal. There are 10k people each of them grows 200 dandelions

[swansont]

37 minutes ago, Hans de Vries said:

Let's say you start with something simple like dandelions.

You want dandelions that are 2x larger than normal. There are 10k people each of them grows 200 dandelions

Are dandelions simple? Is there some simple genetic expression that tells you how big a dandelion will get?

This may be a case where 10k people growing 200 dandelions is no better (or only marginally better) than 1 person doing it. As they say, it take a woman 9 months to produce a baby. 9 women together will not produce a baby in a month.

 

[Peterkin]

It all depends ....

There are too many factors for a simple answer. I don't think the number of people working on it is one of the more important factors: a single insightful and methodical researcher might be more effective than a hundred or thousand random people. Of course, among ten thousands, the odds are better of finding several good researchers. 

OTH, I don't know that dandelions don't have a specific limit to flower size, or stem length or leaf colour variation built into their DNA, so that  you would have to introduce a different species to affect that characteristic. So, if all the original stock is the same, the number makes no difference to the outcome.  

@swansont🙂

Edited September 27, 2021 by Peterkin

[Phi for All]

On 9/27/2021 at 10:08 AM, Hans de Vries said:

Let's say you start with something simple like dandelions.

Simple? There are around 250 species in Britain and Ireland alone. Pick one and you might get meaningful references.