HortScience 23(5):927-928. October 1988.
Schuyler Sari Korban
Department of Horticulture, University of Illinois, Urbana, IL 61801
Jules Janick, Edwin B. Williams, and Frank H. Emerson
Purdue University, West Lafayette, IN 47907
Additional index words. Malus xdomestica, Venturia inaequalis, fruit breeding, disease resistance
Received for publication 10 Dec. 1987. This research was partially supported by funds from the Illinois Agricultural Experiment Station (project 65-325) and from the Purdue University Agricultural Experiment Station (paper no. 11400). We acknowledge the assistance of D.F. Dayton and J.F. Morrisey (Univ. of Illinois), J.A. Crosby and J.M. Ingram (Purdue Univ.), and S. Mehlenbacher and L.F. Hough (Rutgers Univ.) in the development of 'Dayton' apple. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.
'Dayton' is an attractive red apple (Malus x domestica Borkh.) with field immunity to apple scab incited by Venturia inaequalis (Cke) Wint. This apple is named in honor of Daniel F. Dayton, Emeritus Professor and longtime leader of the disease-resistance apple breeding program at the Univ. of Illinois.
'Dayton' is the seventh apple cultivar (1-6) developed by the cooperative apple breeding program of the Illinois, Indiana, and New Jersey Agricultural Experiment Stations. The fruit is large, an attractive glossy red (Fig. 1), and matures with 'Prima' and 4 weeks before 'Delicious'. Fruit is well distributed over the tree and hangs for almost 2 weeks without loosing its firmness and dessert quality. It retains its good flavor and firm flesh up to 4 weeks in cold storage (1°C). 'Dayton' is released as a potential commercial cultivar for use as a summer dessert apple; in addition, it makes an excellent backyard apple.
Fig. 1. Fruits of 'Dayton' apple.
The original seedling was planted in 1969 in a breeding orchard of the Illinois Experiment Station, Urbana, Ill. The seedling resulted from crossing a New Jersey selection, NJ 123249 as pollen parent, with an earlier scab-immune seedling selection, PRI 1235100, as seed parent. The complete pedigree is shown in Fig. 2. The seedling was selected on the basis of pomological characteristics in 1976. Propagated trees have been under test as Co-op 21 at cooperating experiment stations in several states and in other countries.
Fig. 2. Pedigree of 'Dayton' apple.
The new cultivar produces a moderately upright tree similar to 'Delicious'. The fruit is attractive and has a very good, full-flavored dessert quality. The flesh is pale yellow, crisp, juicy, fine grained, and mildly sub-acid.
'Dayton' carries the Vf gene for resistance to apple scab derived from M. floribunda 821 and has shown resistance to the five races of the organism in greenhouse inoculations and field immunity during 12 years of testing in Illinois, Indiana, New Jersey, Oregon, and at various research stations in Canada and Europe. In addition, 'Dayton' has moderate resistance to powdery mildew, incited by Podosphaera leucotricha (Ell. & Ev.) Salm and to fire blight incited by Erwinia amylovora (Burr.) Winslow et al.
The following detailed description follows Zielinski (7) and uses color designations according to the Royal Horticultural Society Colour Chart, issued by the Royal Horticultural Society of London.
Budwood is available only for test purposes at Illinois and Indiana Agricultural Experiment Stations. Trees will be available from licensed nurseries. Plant patent no. 5584 has been granted for this cultivar.