ISHS Acta Horticulturae 411: VII International Workshop on Fire Blight
EVALUATION OF THE RESISTANCE OF APPLE, PEAR AND QUINCE VARIETIES TO FIRE BLIGHT |
| Authors: | A. Maroofi, M. Mostafavi |
| Abstract:
Fire blight has caused economic losses in apples, pears, hawthorn and quince with increasing order in Qazvin, Iran. The susceptibility of 52 apple and 22 pear cultivars were screened on scion shoots in the greenhouse by inoculation with 1 × 109 cells/ml, bacteria of a mixture of five isolates of Erwinia amylovora. A wide continuous spectrum of reaction was observed among the cultivars which was divided into four groups. In apple, the resistant group included the varieties Starking, Improved All Red, Gallobell Blan, Winesap, Red Spar Copper, Meshhad, and Red Spar. The progression of bacteria was limited to 1–2 cm, 45 days after inoculation. A similar resistant group was not observed among pear cultivars. Coscia and Khoj which showed more progression of bacteria were grouped as semi-resistant. In the susceptible group progression of the bacteria was quick, penetrated into the three-year-old wood, droplets of ooze were produced on the branch and it became hooked. Although the symptoms were more severe in the greenhouse, a positive association between natural field reaction and greenhouse symptoms was observed. The local pear variety Darghazi has not shown any disease symptoms in natural epidemics during previous years. | |
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