Baby lima bean holds proud spot in Delaware

By SEAN CLOUGHERTY
Managing Editor

GEORGETOWN, Del. — The baby lima bean may seem small compared to other vegetables grown in Delaware, but the crop as a whole has great importance to the state’s agriculture industry.
Last year, Delaware farmers grew about 19,000 acres of baby limas, according to Gordon Johnson, Delaware Cooperative Extension vegetable crops specialist, making up about two-thirds of the acres grown nationwide.
With a long history of growing limas on Delmarva, limas act as an anchor crop for the processing vegetable industry.
The large acreage of limas makes it feasible for processors to contract more acres of peas and to some extent sweet corn in the area, Johnson said.
Delmarva and California claim the only major growing areas for baby limas in the United States.
Despite cheaper irrigation costs, lower land values than California and its closer proximity to major markets, the Mid-Atlantic region has been at a competitive disadvantage, realizing about half the yield of West Coast growers and saddled with more disease pressure.
All those reasons make the crop worth protecting and improving, Johnson said, and the public breeding program for limas at UD is focused on those goals.
“Unless you have a breeding program for your region you’re not making progress,” he said.
Yield trials for lima beans have been part of Delaware Cooperative Extension’s research program for decades, but the breeding program — started in 2004 — is designed to develop varieties specifically for the Mid-Atlantic environment.
The UD breeding program, led by Emmalea Ernest, Extension vegetable crops associate, essentially picked up where the USDA’s breeding program in Beltsville, Md., left off when in was discontinued in the 1980s.
Beltsville breeders had successfully bred lines with resistance to four known races of downy mildew essentially accomplishing the goal of the program.
However, when two new races of the disease popped up years later, a new resistance issue came with them.
Ernest said of the two companies supplying seed to Delaware growers, neither grows the seed in the Mid-Atlantic region and only one company does its own breeding.
“That meant the crop which is very important to Delaware is not being selected for this environment,” she said.
That gap in breeding improvements led then-Extension vegetable crops specialist, Ed Kee to push for a local breeding program.
Ernest said research from Kee and Extension horticulture agent Tracy Wooten was showing the cultural practices and disease management of existing seed lines would only carry the industry so far in Delaware.
“They came to the conclusion that we were maxed out. What we needed was better varieties here,” Ernest said.
The breeding program began with Ernest gathering material remaining from the Beltsville program and seed from around the world.
“Most of it looked awful,” Ernest said of the first year’s trials, but after several plant generations, better lines emerged and last year two commercial growers planted field trials on their farms with Ernest’s lines.
Field trials on the university farm continue along with Ernest making plant crosses in the greenhouse at the Carvel Research Center in Georgetown.
Last year Ernest was working with about 50 lines and this year expects to have about 80 from which to make selections.
Breeding and selection has largely been focused on developing lines for resistance to the new races of downy mildew while maintaining adequate and stable yield, but Ernest has also begun selection for resistance to Phytophthora capsici, nematodes and traits for heat tolerance.
Seed appearance and feedback from seed companies are other factors always involved in selection, Ernest said, because seed companies won’t use a seed if it thinks the color or shape won’t appeal to consumers.
Ernest said in the next two years, she expects to have lines of baby limas suitable to release for commercial production.
Breeding for Fordhook lima beans is showing promise as well.
Ernest said she has identified lines of Fordhooks with resistance that maintains yield but needs more time to confirm it in field trials.
She said there could be some lines worth releasing in about three years.
“We want high yields but we also want stable yields,” she said.
In the last two years — one a good growing year and the other a bad one — Ernest said a line from her program out performed the standard for Fordhook seed.
“I feel like what I have for Fordhook is much much better than what’s available,” she said.
While Delmarva at one time had a large acreage of Fordhooks for processing, most of the production has moved to California.
With varieties well suited for the peninsula’s growing environment, “we have the potential for bringing almost all of that or a good chunk of that here,” Johnson said.
Overall, Johnson said the breeding program stands as a prime example of the value of Extension and public research.
Public breeding programs across the nation have dwindled due to funding cuts and other factors. In the case of major commodities, private companies have carried on the breeding research but Johnson said smaller crops, like lima beans, don’t carry the same economic incentive.
“Public breeding is at a critical stage in a lot of ways,” Johnson said. “It’s a big issue, particularly in minor crops where the industry isn’t going to pick up the slack.”