Abstract
To examine the genetic differentiation between two ecotypes (annuals and perennials) in the wild rice species O. rufipogon, seeds and juveniles were collected from eight populations in Thailand, and compared regarding both life-history traits and enzyme loci. While no appreciable differentiation was found at the enzyme level, the two ecotypes showed a clear differentiation in life-history traits. This suggests either that gene flow occurs between the two ecotypes and ecotypic differentiation is maintained by selection, or that the annual-perennial differentiation is recent compared to the geographic differentiation between wild rice strains, and the evolution of life-history traits occurred rapidly.
