Anthacnose Fruit Rot Resistance in Strawberry

Abstract

The purpose of this research has been to determine the nature of strawberry fruit resistance to anthracnose fruit rot. Production in the United States and North Carolina is heavily dependent upon two cultivars, Chandler and Camarosa. Both cultivars are susceptible to anthracnose fruit rot (AFR), caused by the imperfect fungus Colletotrichum acutatum. Results from this research will be used to further our understanding of the strawberry-C. acutatum system and to control AFR through breeding strategies or cultural practices. Components of resistance in strawberry to AFR were studied under field and controlled environment conditions; five strawberry genotypes were inoculated with conidia of C. acutatum under field conditions and seven genotypes were inoculated with either five inoculum concentrations or three isolates of C. acutatum in growth chambers. Strawberry genotypes responded differently to C. acutatum in the field and in a controlled environment. Components of resistance to AFR included rate-limiting resistance, reduced percent lesion, reduced probability of lesion formation due to fruit age and genotype, and plant canopy architecture. Rates of disease progress were different among genotypes, inoculum concentrations, isolates, and the genotype x isolate interaction. Susceptible genotypes and virulent isolates had faster rates of disease progress. Differences were observed among genotypes for yield, percent by weight, and number of berries with AFR. Plant canopy architecture influenced the hours of fruit wetness and the yield of berries with AFR; a loose open canopy had fewer hours. Young and old fruit were less susceptible to AFR than fruit of median age.