BRASS, India—The monsoon rains have come late to northern India. In the past, that would have meant certain hardship. But this year, farmers here aren't worried, thanks to new drought-resistant strains of rice that are helping sow prosperity across India's grain belt.

"We're hopeful of a good harvest," said Gurcharan Singh, standing amid green seedlings in his fields here in the north Indian state of Haryana. The fast-growing hybrid variety of rice that he planted on 20 of his 80 acres requires about a quarter less water than standard types.

Two decades ago, a bad monsoon could cut India's annual economic growth rate in half. Today, however, new seeds and advances in drip irrigation and other agricultural technologies are helping to cushion farmers and the economy.

Progress in recent years has been significant. A 19% rain shortfall in 2002 cut grain output 18% and a 22% rain deficit in 2009 dented grain production by 7%, according to government figures. So far this season, rainfall is 25% below average, but economists expect almost no impact on food-grain yields.

Changes in cultivation patterns—these days, monsoon-dependent summer-season crops account for 50% of agricultural output, down from about 66%—and the diversification of the economy away from farming have also helped make India less dependent on the weather.