PRI Disease Resistant Apple Breeding Program

Co-op 1
Co-op 3
Sir Prize
Co-op 6
Co-op 7
Co-op 8
Co-op 9
Co-op 10
Co-op 11
Co-op 12
Co-op 14
Co-op 15
Co-op 16
Co-op 17
Co-op 18
Co-op 19
Co-op 20
Williams' Pride
Co-op 24
Scarlett O'Hara
Co-op 26
Co-op 27
Co-op 28
Pixie Crunch
Co-op 34
Co-op 35
Co-op 36
Co-op 37
Co-op 40
Co-op 41
Co-op 42
Co-op 44

HortScience, Vol. 9(4):401-402, August 1974

'Priam' Apple1

L. M. Decourtye, E. B. Williams,2 Jules Janick,3 F. H. Emerson,3 D. F. Dayton,4 J. B. Mowry,4 L. F. Hough,5 and Catherine Bailey5

Station d‚Arboriculture Fruitiere, INRA, Beaucouze, Angers, France

lReceived for publication March 16, 1974. Journal Paper No. 5452 of the Purdue University Agricultural Experiment Station, West Lafayette, Indiana, and paper of the journal series of Cook College, Department of Horticulture and Forestry, Rutgers-The State University, New Brunswick, N.J.

2Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana.
3Department of Horticulture, Purdue University, West Lafayette, Indiana.
4Department of Horticulture, University of Illinois, Urbana, Illinois.
5Department of Horticulture and Forestry, Rutgers University, the State University of New Jersey, New Brunswick, New Jersey.

'Priam' is a new fall red apple with resistance to apple scab caused by Venturia inaequalis (Cke.) Wint. ripening close to 'Jonathan' and about one week before 'Delicious' (Fig. 1).

Fig. 1. 'Priam' apple.

'Priam' is the third apple cultivar (1, 2) to be introduced from the cooperative breeding program carried out by the Agricultural Experiment Stations of Indiana, Illinois and New Jersey; the U.S. Department of Agriculture; and informally cooperative with a number of other states and countries, namely France in this particular case. The prefix PRI in the name is an acronym formed from the three institutions involved, viz. Purdue, Rutgers, Illinois. The apple was named for Priam the last king of Troy, the father of Paris. The selection has been tested in France and England. It does not show a large area of adaptation but good results have been obtained in some locations in France. High acidity and attractiveness of the fruit are the main characteristics which make this selection outstanding and have led us to release it.


The original seedling was planted in 1952 in the breeding orchard of the Purdue University Agricultural Experiment Station, Lafayette, Indiana. It was produced from crossing the seedling 14-126 as the seed parent and 'Jonathan' as the pollen parent in 1951 at Lafayette Indiana (Fig. 2). The seedling first fruited in Sept., 1956. It was introduced into France from the John Innes Institute (England) in 1958 and had been chosen in 1965 for a mutation breeding experiment which led to the observation of 200 trees.

Pedigree of Priam

Fig. 2. Pedigree of 'Priam'.


The tree is moderately vigorous, somewhat spreading, regularly and heavily cropping. It shows slight mildew susceptibility, similar to 'Golden Delicious' and much less than its parent, 'Jonathan'. It flowers 1 week before 'Golden Delicious'.

The fruit has fine dessert quality but it may be too acid for U.S. tastes before storage. The texture is crisp and the flavor pleasant. The attractive fruits have a green-yellow ground color with 60-90% bright red over color principally as a blush (Fig. 1). They should be picked a week or two before 'Delicious'. Fruits can be stored at 2°C for at least 3 months. The optimum edible quality is from Oct. to Jan.

The following detailed description of the flower and fruit follows the "Guidelines for the conduct of tests for distinctness, uniformity and stability" from the International Union for the Protection of New Plant Varieties (U.P.O.V.), and uses the color designations according to the Colour Chart of the Royal Horticultural Society.


  • Shape: round-conical, very regular.
  • Size: axial diam 6.0 to 7.0 cm (214 to 23/4 inch), transverse diam 6.5 to 7.5 cm (2 1/2 to 3 inch).
  • Color: undercolor "green-yellow" (plate I group D) to "yellow" (plate 3 group D); overcolor 60 to 90% medium red (plate 47 group B to plate 46 group C).
  • Skin: smooth, without bloom, weakly waxy, small lenticels, moderately tough. No russeting.
  • Stem: short, 0.8 cm (3/8 inch), below level of cavity, medium thickness.
  • Cavity: deep (18 mm), broad (35 mm), acute, slight streaky russet.
  • Basin: medium depth, narrow, without ribbing.
  • Calyx: short, erect, convergent, sepal bases free.
  • Calyx tube: Y shaped, closed.
  • Stamens: median.
  • Pistil: persisting, not fleshy.
  • Core: medium size, distinct line, flat-round.
  • Carpels: cell length short, medium breadth, round, open narrow aperture in transverse section.
  • Seeds: medium number, medium size, much longer than broad, moderately thick, obovate, apex acute, pale buff brown.
  • Flesh: "yellow" (plate 11, group D), fine, juicy, medium sweet, acidity strong, aromatic, good quality.
  • Time of fruit maturity (for picking): midseason, 1-2 weeks before 'Delicious'.
  • Time of fruit ripening (for eating): midseason, Oct. to Jan.
  • Use: dessert.


  • Tree: medium vigor, spreading habit, open, tip bearing.
  • Leaves: narrow, length-to-width ratio 1.9, lanceolate, biserrate, long, apex acuminate, rounded base, deep green, wavy edge, petiole length long and green, narrow and long stipules.


Budwood is presently available from the Station d'Arboriculture Fruitiere, INRA, Beaucouze, Angers, France.

Literature Cited

  1. D. F. Dayton, J. B. Mowry, L. F. Hough, Catherine H. Bailey, E. B. Williams, J. Janick, and F. H. Emerson. 1970. 'Prima' - an early fall red apple with resistance to apple scab. Fruit Vars. & Hart. Dig. 24:20-22.
  2. E. B. Williams, J. Janick, F. H. Emerson, D. F. Dayton, J. B. Mowry, L. F. Hough and Catherine Bailey. 1972. 'Priscilla', a fall red apple with resistance to apple scab. Fruit Vars. & Hort. Dig. 26:34-35.

About PRI

Co-op Summary Table

Brief Description

Co-op Release Description

Cultivar Release Description