Articles
SOME FACTORS AFFECTING SELECTION FOR FIRE BLIGHT RESISTANCE IN PEAR
Article number
117_8
Pages
55 – 62
Language
Abstract
Several thousand seedlings of the 1967–1969 pear progenies were inoculated with the fire blight bacterium, Erwinia amylovora, and the most resistant ones compared for 10 years in the field against unscreened sibling seedlings.
Significantly more screened than unscreened seedlings were scored as resistant or moderately resistant in 2 of 4 years’ progenies.
When the degree of fire blight in unscreened sibling seedlings was compared between two locations, significantly more trees were found severely blighted in the Ohio than the Maryland location.
This was probably due to more vigorous growth and more favorable weather conditions in Ohio.
The relationship between the end of juvenility and the incidence of first fire blight in nearly 12,000 seedlings was analyzed.
The mean juvenile period was 5.1 years, and the mean age at first blight was also 5.1 years.
A significant, but small, correlation was found between the age of seedling trees at first bloom and the age when blight first was observed.
These data indicate that the presence of bloom and the transition to the adult phase are not necessarily a major factor in susceptibility to fire blight.
Significantly more screened than unscreened seedlings were scored as resistant or moderately resistant in 2 of 4 years’ progenies.
When the degree of fire blight in unscreened sibling seedlings was compared between two locations, significantly more trees were found severely blighted in the Ohio than the Maryland location.
This was probably due to more vigorous growth and more favorable weather conditions in Ohio.
The relationship between the end of juvenility and the incidence of first fire blight in nearly 12,000 seedlings was analyzed.
The mean juvenile period was 5.1 years, and the mean age at first blight was also 5.1 years.
A significant, but small, correlation was found between the age of seedling trees at first bloom and the age when blight first was observed.
These data indicate that the presence of bloom and the transition to the adult phase are not necessarily a major factor in susceptibility to fire blight.
Publication
Authors
T. van der Zwet, R.L. Bell, R.C. Blake
Keywords
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