More than 30 U.S. farm groups representing tens of thousands of farmers said yesterday that planting genetically modified crops could imperil farmers’ livelihoods because the crops are becoming increasingly unpopular with consumers. The groups also warned that inadequate testing of GM seeds could make farmers vulnerable to “massive liability” from damage caused by drifting pollen and other environmental effects. The organizations called on biotech companies to promote the sale of traditional seed varieties for the coming crop year until an independent assessment of the environmental, health, and economic impacts of GM seeds is available. Some seed dealers are expecting a drop in sales of genetically altered seeds, a dramatic shift from last year when many farmers were enthusiastically buying them.