President Reagan might have elicited a chuckle or two in his State of the Union address the other night by denouncing federal spending on cranberry and crawfish research, but it turns out to be no laughing matter.

Lawmakers on Capitol Hill and researchers around the country were fuming yesterday that their pet projects had been singled out by Reagan as examples of unnecessary spending that he would halt if given line-item veto power.

"It's so sad that the administration's attitude and understanding of agriculture is limited to this," said a rueful Rep. E (Kika) de la Garza (D-Tex.), chairman of the House Agriculture Committee.

Reagan, suggesting that Congress knew not what it had wrought, complained that the omnibus spending bill passed just before Christmas contained hidden millions "for items such as cranberry research, blueberry research, the study of crawfish and the commercialization of wildflowers."

Well, now.

The first to react was the cranberry claque. "Frankly, I don't see what's so funny about cranberry research," said Rep. Don Bonker (D-Wash.). His home district includes most of the state's growers, who actually are Reagan's kind of farmers -- they get no price support loans or direct subsidies.

Added Sen. Brock Adams (D-Wash.): "I am offended by yet another example of this administration's habit of making policy arguments based on arbitrary, misleading anecdotes instead of the facts."

And from Rep. Peter DeFazio (D-Ore.): "It's the ultimate extension of his perverted priorities. This guy derides what I consider legitimate research of benefit to the Northwest. It's outrageous."

The reaction was just as harsh at Rutgers University's cranberry/blueberry research center in Chatsworth, N.J., where the $260,000 federal grant will help breeding and pest control programs already funded by farmers and the state government.

"The agriculture community, farmers, scientists felt the president's remarks were an insult, a slap in the face," a Rutgers official said. "The work being done at the center fits into what agriculture should be doing -- reducing chemical pesticide use and improving plant varieties to deter disease."

New Jersey's senators, Democrats Bill Bradley and Frank R. Lautenberg, who got the money into the catchall spending measure, told Reagan by mail that they would block his plans to kill the appropriation with a budget rescission.

Louisiana Sens. J. Bennett Johnston and John B. Breaux, both Democrats, were just as incensed for Reagan's allusion to crawfish, a Bayou State delicacy that usually speaks for itself. They got $200,000 allocated to Louisiana State University for furthering crawfish development.

They, too, dispatched a letter to the president defending the aquaculture research as "critical" to opening new economic opportunities in a state with three years of double-digit unemployment and "severe recession."

And then, the old Cajun double whammy:

"We note that during your administration aquaculture has been considered so important that we have invested considerable resources through the Agency for International Development for aquaculture programs in many foreign countries," the letter said.

The senators said that the administration has supported grants of $23.4 million to Egypt, $600,000 to Cameroon, $1.3 million to Indonesia and $380,000 to Thailand, all in support of aquaculture. The Thai grant included money to promote seaweed production.

"If we can justify funding such programs in other countries from Cameroon to Thailand, doesn't it make sense to support this kind of research here at home as well?" Breaux and Johnston asked.

Sen. Jeff Bingaman (D-N.M.), who got $50,000 seed money for native wildflower research at New Mexico State University, took similar umbrage at Reagan's poke at the posies. He said the funding could help develop a new industry and create jobs.

"It's got more potential for actually bringing out an economic opportunity than most of the budget," he said. "My own view is that it is better to spend $50,000 in New Mexico for research on the propagation of flowers than to send $8 million to the contras."

De la Garza added a footnote of perspective. "When we studied the sex life of a fly, eventually that became the screw worm eradication program. It saved several billion dollars for ranchers and cattle breeders," he said. "But anybody would call it pork barrel when you study the sex life of a fly."