RT Journal Article SR Electronic T1 Testing Verticillium Wilt Resistance in Urban Norway Maples, JF Arboriculture & Urban Forestry (AUF) FD International Society of Arboriculture SP 317 OP 325 DO 10.48044/jauf.1981.074 VO 7 IS 12 A1 F.A. Valentine A1 K.D. Carlson A1 R.D. Westfall A1 P.D. Manion YR 1981 UL http://auf.isa-arbor.com/content/7/12/317.abstract AB Wilt symptoms in Norway maple half-sib families from open-pollinated seed from a random of street trees in Rochester and Syracuse, N.Y. inoculated with Verticillium dahliae were analyzed for the reliability in predicting disease, variability in the parent population, and heritability. Inoculum was prepared from 11 isolates of diverse origin from maples and reisolates from Norway maple previously inoculated with these stocks. Two replications were inoculated with two inoculum concentratons (2.5 X 106 and 0.5 × 106 pro-pagules/ml) and a distilled water control by dunking wounded roots of 2-0 nursery stock. Disease was verified by isolating the pathogen from stems. Thirteen families averaging 3.5 trees/family/treatment/rep (274 total) were tested in 1979, and 40 families averaging 7.8 trees/family/treatment/rep (1875 total) in 1980. Vascular streaking (dark greenish lesions) and two measures of foliage necrosis (% Crown Necrotic and % Necrosis, Worst Leaf) proved most reliable for predicting infection. These traits are recommended for screening for resistence. Three height growth measures did not prove reliable. Considerable variability is present in the parent populations, but estimates of heritabilities for each trait are quite variable, requiring further study. Increasing the incidence of infection is also important.