After hearing about the things that can go wrong when trying to grow a crop of lettuce, one grower concluded that each perfect head produced is a miracle.
One thing became clear during a seed symposium held Thursday in Yuma – yes, it really does take rocket science or a great deal of luck to produce the lettuce people enjoy in their salads and on their sandwiches.
The trick is to induce a seed for a cold weather crop to poke its head out of its shell into a world that may still be 120 degrees.
“It's a reverse process,” observed Charlie Cain, sales manager in the Yuma area for Seed Dynamics, a seed technology company that hosted the symposium. The event, held Thursday, was attended by approximately 120 people, including farmers, agriculture officials and a handful of University of Arizona agriculture students.
Cain explained that as farmers start thinking about the coming produce season, it seemed like a good time to offer a refresher program on steps taken by science to help ensure they will get a good crop. It was especially fitting after problems farmers experienced last fall with seed that failed to germinate, perhaps linked to the rain that soaked the Yuma area in September just as planting was getting underway.
“Everyone in this room agrees that everyone wants to maximize fields with a good stand and uniform crop,” said Hank Hill, a physiologist with Seed Dynamics since 1991. That means most if not all seeds germinate and each plant grows at the same rate so harvesters can clear the field in one pass and obtain cartons of lettuce that are all the same desired size.
“Missing plants mean fewer cartons per acre and, farmers lose money,” he said. “The lack of uniform size means fewer cartons per acre and farmers lose money.”
The majority of his research has been spent on the development of priming and pelleting products for vegetable and flower seeds to improve their response to environmental stresses.
And there are plenty of those. Plants may decide to remain dormant if they don't get enough light, the temperature is too high and they don't get enough water. Add in a high salt content in the soil that is found in the Yuma area, and it becomes an even greater issue.
“You want all the help you can get,” Hill told farmers.
Priming seed is done by exposing seed to moisture to weaken the endosperm, the layer of cells around the embryo plant. The seed is then dried out and stored until ready to be planted. Pelleting the process of coating the seed to make it easier and more cost effective to plant.
“It's not perfect,” he said. “But you have a better chance. Priming is your insurance policy against bad weather.”
Further complicating the issue are such factors as varieties of seed that respond differently, various ways of treating the seed, the presence of different soil types even in one field and the use of pre-emergent herbicides, noted Dr. David W. Still, a professor and seed biologist at Cal Poly Pomona who previously worked as an assistant research scientist at the University of Arizona Yuma Agriculture Center.
“Sometimes the seed just doesn't germinate,” he said. “Figuring out why is difficult to do.”
He noted that lettuce has 43,000 genes, twice the number humans do. Of those 43,000 genes, roughly 20 percent of them regulate germination. His job is to figure out which ones are critical so he can put people like Hill out of business.
That's not going to happen anytime soon,though, Still assured Hill.