- World Genepool at the N.I. Vavilov Institute of Plant Industry and Its Utilization in Agriculture. Anyone got a copy?
- Gloucester Old Spot pigs get protection. Not that they really need it.
- BASF takes hi-tech breeding to the next level: 40,000 individual rice plants on a robotic ride to the future.
- Rebsie does carrots.
- The perfect storm is one element of the triple crisis.
- Nitrogen-fixing shade trees really do feed young cacao trees.
- “Sheep is your backbone.”
- Bringing gluten-free sorghum beer to the huddled masses … of Colorado.
- Eat like a pope. (Not much diversity.)
- Cadbury heiress fancies starting a new chocolate company? Maybe she’ll go all varietal.
- Scientia pro Publica. Carnival time again.
Nibbles: Haitian mangoes, Dog bones, Vitis in Georgia, Lavandula in Tunisia, Pistacia in Chios, Rice wine in Korea, Nutella, Mozzarella, Gloucester Old Spot, Cowpea
- Buy Haiti’s Francis mangoes!
- The Muge dog was, in fact, a dog.
- Looking at the grapevine in its center of origin.
- Need to fence lavender populations in Tunisia to protect them.
- More Mediterranean stuff. History of the mastic trade in an Aegean island.
- Making “drunken rice” in Korea. Sign me up.
- Nutella to come with warning label? Jeremy says: We don’t need no nanny state!
- Bluish mozzarella balls confiscated. Jeremy says: Ok, maybe we do after all.
- EU makes itself useful and protects bacon pig of choice, with built-in apple sauce to boot.
- “…finding how the physical and chemical composition of different cowpea varieties influence human health, reduce obesity and prevent diseases like cancer, hypertension and heart related ailments.”
Nibbles: Food prices, Exotica, Mint, Walnuts
- “Global agricultural production … on track to satisfy estimated long term demand.” That’s the good news. Food prices to rise by around 40%.
- “Israel plows new ground in exotic crops.” Ho hum.
- US regains global dominance in mint … but at what price?
- Greek walnut trees way out on a limb.
Nibbles: Allium, Desertification and livestock, Striga, Emmer, Hawaii, Almond, Seeds at FAO, Cassava in central Africa, Seed sculpture, Biofortification, Millets, Lunatrick pea
- Botany Photo of the Day is an onion wild relative! Pretty.
- More on that livestock-can-help-reduce-desertification thing, this time from Scientific American.
- Breeding Striga-resistant sorghum. Whatever it takes to protect local beer, boffin-dudes!
- Emmer wheat reviewed to bits.
- No passport data for your barley? Fear not.
- Rachel Laudan ably defends Hawaiian food.
- Origins of almond traced to Iran. Not for the first time.
- Plant Genetic Resources for Food and Agriculture: A Commons Perspective. Presentation from our friends at FAO.
- Presentation on the untapped potential of cassava in the Great Lakes region of Africa. One of many from CIAT lately. Check out their stuff on beans too.
- The Seed Cathedral of Shanghai. Thanks to those public awareness wizards at Kew.
- Big shindig on biofortification. Be there, or be malnourished.
- Times of India bangs the drum for nutritious millets.
- Yet more loveliness from serious amateur pea breeder Rebsie Fairholm.
The long road to perennial cereals
Why are there no perennial grain crops? That’s the provocative question posed by a recent paper in Evolutionary Applications written by three scientists working at The Land Institute. ((Van Tassel, D., DeHaan, L., & Cox, T. (2010). Missing domesticated plant forms: can artificial selection fill the gap? Evolutionary Applications DOI: 10.1111/j.1752-4571.2010.00132.x)) Whose institutional mission, of course, is to breed just this sort of crop, on the assumption that they “could reduce soil erosion while maintaining production of food staples.”
So what’s the answer, and what can be done about it? The authors start by pointing out that if you plot life form against net annual reproductive effort for angiosperms there’s a gap in the graph where herbaceous perennial crops with big, plentiful seeds and fruits should be. You have annual grain crops, of course, and fruit and berry cultivars, but nothing in between. Could it be that this particular “morphospace” is impossible on logical grounds? Or that there has not been enough time for the combination to develop?
After looking at a number of different possibilities, the authors come up with a very stark statement:
We suggest that the simplest explanation for the absence of perennial herbs with high reproductive effort is that, while biophysically possible, this lifeform could not have evolved by natural selection.
Let’s unpack that a bit. The authors point out that wild, out-crossing perennials are great at generating genetic diversity because
…somatic mutation generates heterozygosity in long-lived individuals … and allogamic recombination ‘destroys the associations built by, and favored by, selection’ … yet inefficiently purges deleterious recessive alleles.
This means that high genetic load results (the build-up of lethal recessive mutations), and therefore, the authors argue (with plenty of evidence to back them up), low seed set. Now, couple that with the fact that perennials tend to be ecologically dominant. What do you end up with?
You end up with a bunch of plants which are “poor candidates for rapid natural selection” in the new, open agricultural environments of the Neolithic: slow to colonize, still connected by geneflow to surrounding “wild” populations, and able to spread by vegetative propagation once established. This made “rapid domestication by sexual cycles unlikely.” Rapid domestication by vegetative propagation, yes, but that’s another story.
No wonder that
…domestication of annuals … under natural selection would have been faster than—and probably pre-empted—the domestication of perennials.
So, if you want perennial grain crops, you have to use artificial selection where natural selection has “failed.” The key is to minimize genetic load. You can do that by prioritizing for domestication perennials that are self-pollinating, which tends to be better at getting rid of deleterious mutations. Or by developing inbred lines by selfing and then re-combining the “purged” lines to restore heterozygosity, including in hybrid varieties. Or by selecting forcefully and strictly for high seed set (which has been working, say the authors). Crosses between annual grains and their perennial wild relatives can bring together “domestication traits and the perennial life history,” as has begun to be done for rice, wheat, rye, sorghum and sunflower.
Definitely worth a try. Because, as the authors conclude:
Adding herbaceous grain type crops to the inventory of existing, mostly tree-like, perennial food crops would give farmers additional options for balancing humanity’s demand for both nutritional and ecological services. We predict that artificial selection will open previously inaccessible regions of plant morphospace to agriculture and will reveal that some promising taxa were under-sampled. The grass family, for example, has given us our most valuable grain crops, but 70% of the 8000 grass species are rhizomatous perennials (Crepet and Niklas 2009) and were almost certainly overlooked in the early rounds of domestication which relied on natural selection.