IDENTIFYING SOURCES OF RESISTANCE TO MUMMY BERRY AND ANTHRACNOSE IN HIGHBUSH, RABBITEYE, AND SPECIES GERMPLASM

Abstract

A primary objective of the USDA breeding program has been identifying sources of disease resistance to fungal diseases. A comprehensive collection of highbush blueberry cultivars has been assembled and screened for resistance to mummy berry blight, mummy berry fruit-rot, and anthracnose fruit-rot. Utilizing common standards, results from multiple mummy berry blight screenings have been interpolated to allow a ranking of highbush cultivars. A large collection of rabbiteye cultivars has been similarly screened, and although differences in resistance were found, no exceptional blight resistance, similar to highbush, was identified. Mummy berry fruit rot resistance screening has been completed on 68 cultivars. Species screenings have identified excellent sources of resistance to the two phases of mummy berry with V. boreale and V. myrtilloides notable for excellent resistance to both phases. High density nurseries are being utilized for routine screening for mummy berry resistance among breeding program progenies. Anthracnose screening has screened 87 highbush cultivars and has shown variable resistance with ‘Elliott’ being the most resistant. Effectiveness of field screening for anthracnose resistance is currently being evaluated. Screening results are being used to build a database incorporating disease resistance, firmness, antioxidant levels, flowering time, ripening time, etc.