1. Pioneer Hi‐Bred International A DuPont Company 7300 NW 62nd Ave. Johnston IA 50131‐1004 USA
2. USDA‐ARS Dale Bumpers National Rice Research Center Stuttgart AR 72160 USA
3. Dep. of Plant Breeding Cornell Univ. Ithaca NY 14853 USA
4. USDA‐ARS Crops Pathology and Genetics Research Unit Dep. of Agronomy and Range Science Univ. of California Davis CA 95616 USA