Front Range Seed Analysts
1994 Seed Forum Volume 8 Number 2
Spotlight on a Lab: Mesa Maize
By Bill Ebener
I had just finished reading the February issue of Seed Forum, cover to cover no less, when my gaze focused on the small box of information regarding the next issue. "Spotlight on a Lab: Bill Ebener at Mesa Maize." The letters registered in my brain, but their significance totally escaped me at that moment. Seconds passed while I cogitated on the particular arrangement of those 36 letters. "Yes," I shoutedusing the same tonal inflections as heard during the movie Home Alone, "that would be an excellent article for me to read because Annette has requested a similar regarding my lab."
Well, to make a short story long, you will need MRI if you want to focus on the seed lab at Mesa Maize. At the moment the "lab" resides mostly in my imagination. Yes, a building does exist, located amid the adobe "bumps" that dot the foothills of the western slope, just east of Olathe, Colorado. Inside the building we have 428 12" by 12" vinyl floor tiles, 6 four tube fluorescent lights, a large (6' diameter) round table, and yours truly, me. Of course we are in the process of further equipping our lab, but, essentially this "lab" is adequate.
Mesa Maize specializes in seed production for the sweet corn hybrids that we develop. All of our hybrids are homozygous sugary enhancer (SE) single crosses that are selected for early maturation (~70 days). We develop the hybrids (I'm told that one must examine 10,000+ crosses before one stumbles across a potential new variety, the "pipeline" in breeder jargon); produce the inbred seed in quantities sufficient for our hybrid seed production; produce the hybrid seed; clean, bag, market, and ship the hybrid seed production.
Part of my responsibilities in clude the assessment of purity (mechanical and genetic) and germination for the inbred and hybrid "varieties." Each "variety" is sized into four classes, each seed size becomes a seed lot. Seed lot size can vary from less than 50 pounds to more than 20,000 pounds. From Octoberthrough March I test representative samples of the sweet corn seeds that exit our "mill." As of March 22, 1994, I have tested over 700 samples.
After testing the moisture content of each lot, we check for varietal purity. This information must be obtained quickly because we rely on a large seasonallabor force (each seed is examined, by machine and humans!!!, for varietal purity, mechanical damage, and/or evidence of contamination by disease). Lots that do not meet our standards are re-run and re-tested.
Once a lot meets varietal purity standards, it is tested for mechanical purity (according to AOSA Rules). Last season, our most common reason for rejectinga seed lot for purity reasons was the presence of field bindweed. The fruit's size prevents removal during screening; it "floats" with good seeds. The fruit then dries and breaks open during subsequent handling, releasing bindweed seeds throughout the lot. After the hybrids, the inbreds are run and tested in a similar manner. In addition to the purity information, each lot must be assessed as to the number of seeds per pound and have an appropriate planter plate size determined (this is done empirically and requres much time).
Germination tests are done on 400 pure seeds. We use two towels (#76 weight) with 50 seeds per "towel unit" and place the rolled replicates inside a loose fitting plastic bag (does not cover the "top"). Two sets of 400 reps are placed inside a five gallon plastic pail. Saran wrap, with many tiny holes, is used to "seal" each pail. We have converted a forty foot ex-refrigerated trailer into a "live-in" germinator (25 C with fluorescent lighting) which is capable of holding over 200 tests at one time. The tests go 7 days before seedling evaluation. Normal sweet corn germination is very, very intolerant of excessive water during the test. Ideal towel moisture content at planting can best be described as dry, just a few notches above bone dry. It is my experience that many sweet corn seedling abnormalities can be attributed to excessive moisture during the test, expecially at imbibition.
I suspect I've run up my allotted space, so I will close for now. I will be attempting to become an RST in 1995 and perhaps Annette will allow me to share some of my experiences with you all. If you are ever over on the western slope, please stop in and say "Hey." I would be happy to show you around. If you arrive in late August we can go cooning (read: removing large quantities of sweet corn from grower fields at the exact point of eating perfection).
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