IT NEVER FAILS. Just when a fruit or vegetable comes along that makes all the waiting worthwhile, American agriculture finds a way to muck it up.

We're talking apples here, specifically the Granny Smith, and you can mark this down. They're about to do to Granny Smith what's been done to the tomato, the peach, the strawberry and a hamperful of other farm products that simply are no longer as succulent or as edible as they used to be.

Not much needs to be said about the reasons for this. Modern factory-style farming and supermarket merchandising techniques have taught the consumer that he can have what he wants, when he wants it, whether it's in "season" or not. If it's picked green and sent to market rock-hard, so be it.

But there is plenty of evidence that consumers are rebelling against the system that brings them the superbly colored, blemish- free, cosmetically appealing perishables bred for ease of transport and storage rather than taste.

Consider the apple. Some of the best evidence of a consumer rebellion comes from the apple industry itself. Apple pundits and trade publications express increasing concern over the quality and marketability of America's No. 1 commercial apple, the Red Delicious. Almost 77 million bushels were grown last year, about 71 million this year -- more than twice the amount of its sister, Golden Delicious.

The only way for the industry to dispose of this many apples is by stretching the season with a long-term storage technique known as CA, for controlled atmosphere. The Red Delicious keeps reasonably well and brightens nicely with doses of ethylene gas.

But inside that strikingly attractive crimson peel resides a mealy interior -- a result of long storage, some say -- that is the antithesis of the scrumptiously crisp apple many consumers fondly think they remember from their childhood. A mealy apple just doesn't get it.

The counterpoint to this is the Granny Smith, which the Stark Brothers nursery catalogue correctly says "everyone is raving about." Fresh off the tree, the green- skinned Granny is a crunchy, tangy delight -- and consumers are buying it so avidly that orchardmen see it as the fruit of the future.

There's only one problem with the Granny Smith. We don't grow enough of them to satisfy the demand and many, many bushels of them (not even the government knows exactly how many) are imported from France, Chile, South Africa and New Zealand. Industry sources estimate Granny imports at between 4 million and 5 million bushels.

A decade or less ago, most of the Granny Smiths available in U.S. markets were imported. But, sensing the apple's appeal, American orchardists began planting the Granny. The first important quantities of them are now coming into production, with the Agriculture Department estimating that 3.5 million bushels will be harvested this year, compared to the 2.9 million in 1984.

Again, no one knows how many Granny Smith trees have been planted since the boom began. But the boom continues and most of the major suppliers of trees for commercial growers continue to tout the Granny as the tree to plant. Thousands of acres of other varieties are being chopped down to make room for Granny Smith. And already there are complaints inside the industry about immature, off-flavored Grannies going to market and giving the fruit a bad name.

All of this has a familiar ring. The Golden Delicious went through an almost identical boom 30 years ago when it caught the public's fancy. A limited number of orchards grew it, a few packers marketed it as a premium fruit and they got top dollar for a top product. Then everybody started growing it and quality went downhill. The Golden Delicious faded as just one more fruit, even though it is the No. 2 commercial apple grown in the United States.

There are reports now that Granny Smith plantings are so extensive that within five years American growers may be turning out a spectacular 20 million boxes annually. Obviously, they all can't be sold at harvest or turned into pies and juice.

The answer is the controlled-atmosphere storehouse, which will allow growers to stretch the Granny Smith's selling season and theoretically make beaucoup bucks. The very same thing they did to the Red and Golden Delicious. The very same thing that turned off the consumer.

"Our goal is to have market continuity," Larry Sewell, marketing director for the largest grower of Granny Smith in California, recently told The American Fruit Grower magazine. "We expect at least 60 percent of our Grannies to be in CA storage, so we can move them as demand dictates."

Other growers will follow suit because it's the only way to go. So kiss Granny Smith goodbye. They're about to muck up another good thing.