Purdue University has won a $2 million federal grant to lead a push to breed new varieties of organic tomatoes resistant to diseases that can decimate tomato fields. The grant from the U.S. Department of Agriculture's Organic Research and Extension Initiative will also help researchers identify ways to reduce disease pressure while protecting soil and water quality. Purdue assistant professor of horticulture Lori Hoagland is leading the tomato project that's also enlisted scientists at four other universities and the Organic Seed Alliance. The researchers will investigate ways that farmers can avoid plant diseases such as early blight, late blight and leaf spot. Tomato growers often plant heirloom varieties rather than newer disease-resistant hybrids because of the heirlooms' appetizing taste. But heirloom varieties tend to be highly susceptible to plant diseases.