According to an article on CNN, during the existence of "modern" humans, we've relied on over 10,000 different plant species for food. Nowadays, we only have 150 species under cultivation. Of those, just 12 species provide 80 percent of all of our food needs and rice, wheat, maize and potatoes supply over half of our energy requirements.

China has lost 90% of the wheat varieties it had 60 years ago. In the USA, over 90% of fruit tree and vegetable species under cultivation at the beginning of the twentieth century have disappeared. Mexico has lost 80 percent of its corn varieties and India has lost 90 percent of its rice varieties.

This has been due to increased commercialization and more worrying - the control of a few big companies who are also attempting to manipulate and own what food crop species are available (I kid you not). In the case of Mexico, GMO corn is already "infecting" what few varieties they have left.

That's worrying enough in itself, but what happens if a disease wipes out a particular species we depend upon? It's happened before - the Irish potato famine and the southern leaf blight fungus in the 70's in the USA.

As mentioned in my article on heritage and heirloom seeds, we can play a part in preventing this crop monoculture scenario by getting away from the big seed companies and planting varieties not commonly found. For example, how about purple carrots?

Another example - it's amazing how many different types of tomatoes are out there if you hunt around. I'm taking a crack at planting Galapagos Tomato this year as it's supposedly very drought resistant and salt tolerant - important attributes in this part of Australia where there's a drying trend due to climate change.

Next time you're planting out your veggie garden, be daring and try some heirloom and heritage varieties; then share the seeds with your friends and neighbors!