May 20th, 2011: We gathered under an EZ-Up tent-- the only shade available in a field of wheat. We were assembled at the Lake Wheeler Field Laboratory in Raleigh to see the Uniform Bread Wheat trial plots and hear from USDA-ARS wheat breeder, Dr David Marshall, as well as USDA-ARS plant pathologist Dr Christina Cowger. The Lake Wheeler Field Laboratory is the main breeding station for the Uniform Bread Wheat Trials, propagating hard wheats and some soft wheats as well as a bit of barley and oats. It is one of 11 sites ranging from the panhandle of Florida all the way up to Pennsylvania and over to Kentucky.
Spanning Lake Wheeler Field Lab's 25 acres of trial plots, 1500 populations from different crosses exhibited varying degrees of maturity, height, awn and awn-less, red wheats and white wheats. The combination created a striking patchwork effect. Dr Marshall explained the orderly process of breeding for the best genetics-- disease resistance, yield, and quality baking performance. (And btw, this is old-school breeding practices, not genetic modification.) Crosses begin in a greenhouse up the road and those first year varieties or F1 are grown in a single row in the field. A good bit of these crosses are made between ancient germ plasm from the Fertile Crescent such as emmer and goat grass, and new genetic material. Dr Marshall likened the process of breeding to herding cats, explaining that all the way to F4 (or year 4 material) the genes are still segregating. Varieties that make it to the advancing lines-- the elite material-- are grown in fifty foot plots. Next week, on Tuesday June 7th from 3-5 p.m. we will gather again with Dr Marshall, this time at the Mountain Research Station in Waynesville-- the smallest of his sites-- where one acre's worth of trial plots display largely the elite material that he hopes will eventually be released to the public as long as the lines make the cut, meaning strong disease package, good yield, reasonable maturing time, quality baking performance... And I should mention, in case it is not obvious, this is a public breeding program and Dr Marshall is a public breeder.
Following Dr Marshall, Dr Christina Cowger spoke about mycotoxins, the range of toxic fugal infection that can strike grains. She specifically addressed scab or Fusarium head blight, which can produce two mycotoxins-- deoxynivalenol or DON and zearalenone. These mycotoxins can cause severe gastric irritation in animals and humans. Wheat is most vulnerable to infection during flowering stage and the 10 days following. The main culprit is wet, humid weather two weeks before flowering. Cowger described some of the visual indicators of infection-- diseased spiklets become bleached or tan in appearance, grain exhibits pink tips-- and other indicators include low test weight. The FDA's recommended threshold is 10ppm for poultry and cows, 5 ppm for swine, , and 1 ppm for humans. She explained that for organic growers, who cannot simply spray fungicides, the best defense is going to be variety selection and/or selecting more than one variety, thus staggering harvest (and flowering times). Another defense is crop rotation. And Scabsmart.org can assist growers in managing risk with an online Fusarium Headblight Risk Assessment Tool. For testing on farm, kits are available through Seedboro and similar companies. For lab testing-- I have been told the the NCDA Consumer Services does testing, but I have yet to find an individual at the NCDA who can confirm this info. There are other private labs though that do such testing.
I realize this post is getting a bit long winded for a blog, so just a brief mention of the other presenters-- Dr Chris Reberg-Horton of NC State University spoke on organic production methods, pointing to variety selection as the organic grower's biggest tool. And Carolina Farm Stewardship's Karen McSwain spoke about the EQIUP-OI program as a potential resource to growers interested in growing grains (more on that in a later post).
from the ground up,