Senate Majority Leader Robert J. Dole (R-Kan.), frustrated by continuing delays, threatened yesterday to bypass the Agriculture Committee and take his own 1985 farm bill proposal to the Senate floor for debate next week.

Dole indicated he would give the committee one more chance on Tuesday to come up with an agreement on the wheat and feed grain price-support section that has kept the senators tied in knots for weeks.

If that doesn't work, he said, "I think the only way to bring this to a head is to call up a bill on the floor and see what happens."

Committee Chairman Jesse Helms (R-N.C.), equally frustrated, agreed with Dole's unusual plan and called the failure of his panel to produce a farm bill after its 27th markup session yesterday "at least 98 percent the Democrats' fault."

In session after session, the committee has haggled over ways to hold down federal farm spending while expanding exports and propping up income in the sagging farm economy.

But Helms and Dole got a jolt earlier this week when the committee voted 9 to 8, with Sen. Mark Andrews (R-N.D.) joining the Democrats, to freeze subsidy payments to farmers for four years instead of one year, as the bill pushed by Dole and Sen. Edward Zorinsky (D-Neb.) provides.

Administration spokesmen said the longer freeze would add about $8 billion to the cost of the pending committee measure, which already was about $5 billion over budget guidelines.

Frustration peaked yesterday after Democrats rejected a GOP compromise that called for a two-year freeze and provided that the farm bill be sent to the Senate floor in pieces, a move the minority feared would jeopardize the food stamp and farm credit sections.

And Sen. David H. Pryor (D-Ark.) added a new wrinkle by proposing that the four-year payment freeze also be extended to cotton and rice farmers, adding more to the cost of the bill. Pryor prevailed, 10 to 7.

Dole, seeing he was losing ground, then withdrew an amendment offering a two-year freeze on the target price payments and indicated he was ready to bypass the committee and seek a floor vote.

Dole drew a line in the political sand earlier this month by insisting that the committee move more quickly so that wheat-state senators such as himself could give farmers a clear idea of the shape of new farm legislation during the August recess.

The committee then missed a self-imposed July 15 deadline for reporting out a bill.