 |
| Fat-tailed sheep land-races are common in desert areas where the calories stored in their tails are essential for weening lambs when droughts strike. As improbably as it seems, this might be a good trait to have for sheep colonizing Greenland, for instance. |
Landrace Gardening: Food Security Through Biodiversity And Promiscuous Pollination by Joseph Lofthouse
If you were to to go back in time to the early 1800s and perform a survey of what small-holders were growing in their fields and orchards and had grazing in their pastures you would have found a loose swarm of sort-of-similar plants and animals of varying sizes, shapes and colors.
There would have been a few exceptions. Merino sheep, for instance or race horses. Small grains would have had a similar ripening season but varied wildly for height. But for the most part you would have found a high degree of variability in any given field.
Suppose a valuable mutation occurred in a rye plant in Cornwall. If it had a significant advantage in terms of disease resistance or productivity then the percentage of plants carrying that mutation would increase in the field(s) of the farmer whose field it originally showed up in.
In time, neighbors would notice. They might say "Iaon, my seed seems to have played out. Can I trade some firewood for a few pints of your seed?" Or maybe his sons would plant their fields with the better seed.
Over time, the enhanced seeds would slowly ripple out over the countryside like ripples on a farm pond after a rock had been chucked into it.
Other mutations from other places were also simultaneously rippling out from their places of origin. Seed from distant countries would enter ports and some would inevitably enter into the seed pool. Much of it was unsuitable but some would show advantage. Even the unsuitable would contribute its pollen to the swarm and some of the genes would be shuffled into the deck.
As Asimov observed, in a universe of infinite numbers the unlikely becomes inevitable.
A vulcano in the south Pacific blows up and lowers the temperatures by 5 degrees? Not so much of a problem if the genetic swarm (i.e. landrace) is sufficiently broad. Some of those seedlines originated at higher elevations or in Scandanavia (Vikings got around, don't you know).
Things changed drastically in the mid-1800s. I blame county fairs. To win a ribbon the produce had to fall into a specific category. Inbreeding became the name-of-the-game. Inbreeding and increased uniformity comes with a high cost.
The first cost is the probability of hidden recessive genes reinforcing and manifesting. It is very, very rare that those hidden genes are advantageous. Many breeds of dogs, for instance, are prone to congenital problems. The smaller the population of those breeds the more intensive the inbreeding and the more frequent the problems.
The second cost is the loss of an elusive trait sometimes called "livability". Livability is a general robustness. A purebred Merino might drop its lamb(s) in a snowbank and walk away. The bloodline has been selected purely for fineness and amount of wool at the expense of pedestrian traits like "mothering ability". A crossbred ewe might lamb during a snowstorm but is more likely to stay close to her lamb(s), dry them off and encourage them to get a full belly of colostrum.
That Merino ewe might average a bit more than one lamb a season while the crossbred ewe might average a bit less than two lambs a season. Embroyos must survive in the uterus before they have the chance to survive outside.
Joseph (great first name!) Lofthouse makes the case that if you are pushing the geographic frontiers of a species or if you anticipate sudden shocks in weather or the availability of inputs (feed quality, fertilizer, availability of medicines) then the most rational approach is to plant a butt-load of seeds from wildly varying sources and let Mother Nature sort them out.
I think the same general idea applies to the people we socialize with. That is one of the beautifull things about the internet. I can converse with people all over the world. I can do business with people with very different politics. I can learn things that would otherwise be hidden from me.
But at the end of the day, the bottom line is the number of lambs that make it to slaughter weight, the number of bushels of grain that make it to the bin and the pounds of potatoes that go into the root cellar.
Hat-tip Lucas Machias
Results count. In every field.
ReplyDeleteGenetic variability is the most important course to pursue in my personal kingdom view. Such as the Fainting Goat . One never knows what will come out . The ability to thrive on basic sustenance and against all odds . Blue Lake green beans have done their time in breeding circles and have been endowed with selective traits found in no new type beans . They may be 12 inches long or n3 inches but they all are resistant to most common pests and diseases because somebody was watching and selecting natures best offering . We do it here with those plants and critters that thrive and resist . Matter of fact that's what most of Joes crew are doing . Thriving and resisting .
ReplyDeleteMono-culture agriculture may be locally optimal (short term results, i.e. for a few decades or more), but there is no guarantee that it will lead to a global optimum. Any sudden perturbation in environment (weather, pests, diseases) could result in widespread crop failures and massive starvation.
ReplyDeleteIn other words, losing crop diversity may end up putting us on a dead end of the evolutionary tree.Modern agriculture has selected genetically modified hybrids to get higher yields, pesticide resistance, ease of mechanical harvesting, and other reasons I'm not aware of. It's an inherently unstable approach, long term.
As a gardener, I try to find interesting but unusual plant types, preferably open pollinated heirloom varieties and not hybrids. It may not give me the best yields, but it less likely to be wiped out by some common pestilence that sweeps through.