Quince (Cydonia oblonga) emerges from the ashes of fire blight

Authors: BOBEV, SVETOSLAV - Agricultural University Of Bulgaria; ANGELOV, L. - Agricultural University Of Bulgaria; GOVEDAROV, G. - Agricultural University Of Bulgaria; Postman, Joseph

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2010
Publication Date: 12/31/2011
Citation: Bobev, S., Angelov, L.T., Govedarov, G.I., Postman, J.D. 2011. Quince (Cydonia oblonga) emerges from the ashes of fire blight. Acta Horticulturae. 918:911-915.

Interpretive Summary: Quince is an important, traditional fruit in Bulgaria, but is very susceptible to the bacterial disease fire blight. Fire blight spread to Bulgaria 20 years ago and killed most quince trees. Diseased quince trees provide a source of inoculum resulting in the spread of the disease to other crops like apple and pear. Seedling quince trees were grown from crosses made between surviving trees that exhibited good resistance to fire blight. After several natural fire blight epidemics, 19 seedlings that had both good fruit quality and good fire blight resistance were selected for further evaluation. This paper reports the introduction of several new quince selections that combine resistance to fire blight with high fruit quality and will enable the sustainable production of this crop. Resistant quinces have potential as rootstocks for both pear and quince, thus reducing disease incidence in both crops. The use of fire blight resistant quince trees will not only reduce disease incidence and improve quince production, but will also reduce inoculum levels and benefit the production of other pome fruit species.

Technical Abstract: The two-decade history of fire blight in Bulgaria revealed quince as one of the most frequently attacked hosts and its production on a large scale has almost been entirely eliminated. Nevertheless, this species will play an important epidemiological role as a permanent source of inoculum for other potential hosts because of its traditional presence in many private yards, and its bloom period during favorable fire blight conditions in the late spring. Fire blight disease evaluations were made for 3 years in a collection of the most important quince cultivars in Bulgaria. Two native cultivars, Hemus and Triumph, were found to have high levels of field resistance (Bobev & Deckers, 1999). The promising resistance response of these cultivars encouraged a 10-year program which examined the fire blight resistance of 274 hybrid progenies (3 replicates per combination on the rootstock BA 29). Under natural epiphytotic conditions in 2003 and 2005, a group of 19 progenies were selected because of their significant resistance to fire blight. These selections produced less than 15 blossom and shoot infection points per tree, and less than 5% blighted canopy under high disease pressure. New quince selections that combine resistance to fire blight, high fruit quality, and suitability for compote processing, will enable the sustainable production of this crop. Resistant forms could also be examined as potential rootstocks for both pear and quince, thus preventing more devastating disease in both crops. The use of fire blight resistant quince trees will not only reduce disease incidence and improve quince production, but will also reduce inoculum levels and benefit the production of other pome fruit species.