Cassman, who once ran the International Rice Research Institute (IRRI) in the Philippines, echoes Sinclair on the tardiness of biotech’s promises. “Do you realize that (weed control) traits were discovered in the late 1980s and released in the mid-1990s? We’re 16 years down the road and there’s nothing released with biotech traits that come close to those.

“The point is, (biotech) progress has been much slower than many predicted. The question is whether there really are major advances coming soon. Or is the biotech check continuously in the mail? The optimism expressed (by biotech proponents) is worth questioning.”

With the world “under pressure to meet food, feed, fiber and fuel demands … we need to have a correct vision of understanding where productivity gains will come from.”

Suggestions that major biotech breakthroughs are just within reach — “when, in fact, it’s been 16 years without such a breakthrough despite a massive increase in investment in both the public and private sectors — one has to question whether the goods will be delivered,” says Cassman. “The reason that is so important is that if it is unlikely to see such breakthroughs we need to look at other areas for major productivity gains.”

Sinclair is worried about the “unrealistic view” that crop yields will continue to increase to very high levels because it “shades how agriculture operates in the United States.” He and colleagues “are rather convinced we’re approaching the maximum yield we’ll see in most crops. We aren’t going to be able to gain new, huge yields. Claims by companies of such big yield leaps simply can’t happen because the resources aren’t available.”

In the United States, “we need to begin to consider how to deal with (stagnant) yields. That has a lot of policy implications — one of them is biofuels. How can we talk about corn and soybean being major contributors to biofuels when yields won’t continue to rise? We’ll need those acres for food, both domestic and for export.

“I’ve heard arguments including ‘biotech will provide large yield increases.’ I’m convinced that can’t happen — we have neither the water nor can the plant take up the nitrogen to produce yields that GM companies like to predict.”