Abstract
Fragaria×Ananassa Duch. cv. Toyonoka is a main variety of strawberry in Japan, but it is susceptible to a pathogenic fungus, Sphaerotheca humuli. Rice chitinase gene under the control of cauliflower mosaic virus (CaMV) 35S promoter was introduced into the strawberry plants using Agrobacterium tumefaciens. The transgenic plants showed an increased resistance to the powdery mildew, S. humuli.