Tuesday, March 11, 2014

At the 2014 Sustainable Agriculture Conference: Plant Breeding Workshop

This year's SARE conference, officially the 10th annual Alaska Sustainable Agriculture Conference, hosted by CES, is being held at the Wedgewood Visitor's Center in Fairbanks. The conferences start with a pre-conference workshop day, usually one full-day workshop and one or two half-day workshops. This year's workshops included one on plant breeding and one on record keeping and taxes for agricultural businesses.

I'm at the second half of the preconference workshop on participatory plant breeding, taught by Jim Myers of Oregon State University. We've been covering plant genetics and the difference between inbreeders (selfers) and outbreeders (crossers). It's a bit of an intense short course! I was taking notes earlier for this workshop, but lost them all on the laptop computer when I shut down for lunch. Lunch was pretty good, especially the potato chowder made from local potatoes! I went back for three helpings. (Several businesses contributed locally grown food to the lunch spread, including Basically Basil, Johnson's Family Farms, and several others. Unfortunately, I don't have the list. I'll post the company names here as I find out.)

Fortunately, Myers gave us all a CD with the full notes from his Horticulture 433 class, which is what he condensed part of his workshop from. It describes various systems of classification, from frost or cold tolerance, optimum temperature range, parts used for food, cultural groups, and botanical classification. There's 187 pages' worth of information on specific vegetables. It makes me want to cackle aloud.

Okay, so back to the notes I took from the workshop.

Myers gave us a short overview of the history of genetics and breeding in general, and how Gregor Mendel and his famous pea experiments were rediscovered in the early 1900s. We reviewed dominant and recessive genes, homozygosity and heterozygosity, and terms like allele and locus. Quite intense, as I said, and I won't go into the full details here (I can't remember them all, for one thing), but I'll explain a few things we went over.

In genetics, plants can be divided into those that have evolved such that they require no or very few crossing with other plants to maintain fertility and vigor (inbreeders or self-breeders, selfers for short), and those that do require it (out breeders or out crossers).

Inbreeders include:
  • tomatoes
  • eggplants
  • most peppers
  • beans (but not Scarlet Runner beans) (Fava beans are in between an inbreeder and an outbreeder, so one can use a small stock but not as small as true inbreeders.)
  • peas 
  • lettuces
Selfing a plant that is an F1 hybrid is a way to stabilize a variety for release. "F1" means the first generation between the cross between two distinct parents. Your hybrid starts out completely heterozygous (mixed genes of all sorts of traits). To make the plant breed true, or stabilize, breeders typically self 5 to 6 generations.

Nightshade family flowers in general have a higher percent of outcrossing, but still maintain selfing. Tomatoes may vary: some tomatoes have a style that sticks out beyond the flower (wild types), which will lend them to outcrossing.

Outcrossers include:

  • mustards & brassicas, arugula
  • melons & cucumbers, curcubits
  • mustards have a sporophytic incompatibility: chemical self-pollination prevention
  • corn (each seed has an individual silk down which pollen may travel)
  • artichokes, daisies, sunflowers
  • carrots, Queen Anne's Lace (protrandry: wind pollination)
  • chenopod flowers
  • onion family flowers: protrandry, vegetative bulblets (walking onions or Egyptian garlic also)

No comments: