Tuesday, August 29, 2017

Effects of Domestication on Plants

I've been quite busy lately with a new project, so I haven't been posting much. But within another week or so the task will be essentially completed and I'll fill you in on the story. In the meantime, you'll just have to amuse yourself with the news of Hurricane Harvey. 40 inches of rain! I sat here once during a 13" rain in 24 hours, and it was like being under a waterfall. Houston is getting 20" in 24 hours in spots. Incredible! 

Anyway, don't ask me why but today I got to thinking about how farmers and gardeners changed our foods to suit their needs. I've been doing it myself on a small scale, such as saving my seeds from the early maturing plants, or ones with stronger stalks.  After a few hours of musing it over while working on my project, here's what I came up with........

The scientists are thinking that domestication of plants began 10,000 years ago. So it's been a long time, at least 10,000 crop harvests. Lots of changes happened along the way. What changes still benefit us nowadays? Lots! It's a huge involved topic that books can be written on. But I just want to mention a few things that may help explain some things for gardeners and new small farmers.

I'm comparing the wild relative (if it still exists) with the domesticated version.....

1- Size of plant parts. Domesticated fruits and veggies are often significantly larger than their wild cousins or ancestors. For example, ancestral peppers and tomatoes are quite small, the size of a large modern pea. I tried growing a "wild type" tomato, and it was a whole lot of work and a lot of square foot of growing space for just a few cupfuls of teenie tomatoes. Unique and groovy, but not much bang-for-your-buck. 
2- A different shape. Gardeners intentionally select for shape, such as straight greenbeans, rather than curly ones. And although many small and unusual shaped eggplants still exist, the current preferred eggplants in the US mainland are the large varieties. Other veggie examples -- beet size and shape has changed a lot along the way. Same for carrots. 
3- Larger seeds. Studies found that seed size increased with domestication, even for seeds we don't eat. But sometimes growers intentionally selected for large seeds, such as with corn, lentils, wheat, beans, peas. 
4- Resistance to bugs. Some varieties within a veggie family actually withstand bugs better than others. Growers noted that and selected for it. For example, corn growers often try to select for tighter husks in order to thwart pests. At one time I used to grow a purple cauliflower that almost never had caterpillar damage. It was a hybrid that's no longer available, and I still rue the day I failed to vegetatively propagate it. While the wild counterpart of our domestic veggies often have good insect resistance, it's not always the case with our domesticated versions since selection has significantly changed things. 
5- Disease resistance. Many domesticated varieties seem to fare worse than their ancestral types, but others fare better due to selection. Gardeners often choose varieties that have some resistance to the common diseases in their area. 
6- Adaptation to a region. Many fruits and veggies now grow in conditions that would kill their ancestral parents. Over time, all sorts of survival traits were selected for. Frost resistance, wind resistance, drought tolerance, salt tolerance, just to list a few. The low chill requirements of some fruit trees actually is beneficial for us in Hawaii. But their ancestors required far more chill in order to set fruit. 
7- The plant itself was structurally changed. For example, wheat stems have become stronger and shorter. Bean pods don't shatter when mature and dry. Some pea varieties produce excessive amounts of tendrils. There are beans that are bush habit rather than vining. Modern corn produces tasseled ears covered in a leafy husk. Some veggies today don't look much like their ancestors, 
8- Earlier maturation. Seed savers tend to select for an early harvest, thus we now see beans producing in 55 days rather than taking an entire summer to grow. Many tomatoes are early, quick producers compared to varieties even a century ago. 
9- Long holding ability on the plant. Commercial growing has influenced this trait. As a result of big farmers needing to have flexibility in harvesting times, seed producers selected for strains that would approach ripeness then slowdown, thus having the fruit or veggie stay "nice" for a week or more before being harvested. Ancestral veggies and fruits had no need for this trait. 
10- Higher or lower plant components. We now see some corn varieties that have significantly higher levels of carotene. Other fruits and veggies may be less astringent than their wild cousins, sweeter, or even have a different flavor altogether. Fiber content can be way different. A prime example is wild mangos which are so fibrous as to make fresh eating unpleasant, while domesticated types are a joy.....no strings caught between your teeth.  
11- intentional hybridization to create a more usable plant. What I'm thinking about is sugar cane. Modern cane is by far more usable than either of its parents. 

I'm sure there's plenty more examples to list. I'm just musing over the differences that domestication makes and how it effects me.

When it comes to growing food for myself, I happily taking advantage of domestication. While I know that domesticated foods most likely wouldn't survive without man's help, I have no issues with the idea of growing them under man's care........in this case, this woman's care -- me! 

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