Testing of Czech cultivars and advanced selections of apples for fire blight ( Erwinia amylovora ) resistance

摘要

Five apple cultivars from the Czech Republic and 26 selections from the same country (a majority of them were resistant to scab) were included in the present study. M. robusta strain (Nr. 5) was used as a control with the highest level of resistance to fire blight. Another 7 cultivars with different levels of resistance or susceptibility to the disease were also evaluated. Selena and Nabella were found to be resistant, whereas Angold, Resista and Topaz were susceptible. Two HL selections were previously identified as highly resistant, 3 selections as medium resistant and 7 others as moderately susceptible. The rest of the 14 selections ranged from very high susceptible to medium susceptible. A high level of resistance was confirmed in 3 cultivars from Dresden-Pillnitz: Reanda, Remo and Rewena. Comparison of the parentage of the tested cultivars or selections with their level of resistance to fire blight suggests that most of the resistance comes from Malus floribunda, which was used in the course of their breeding as a donor of scab resistance. In one case, the source of the fire blight resistance was Starking Delicious cv.