■6- 



PERFORMANCE OF DISEASE RESISTANT APPLES IN MASSACHUSETTS 



Christopher M. Beckerl Daniel R. Cooley, 

 and William J. Manning3 



Department of Plant Pathology, 

 University of Massachusetts, Amherst 



A number of apple cultivars, with immunity to apple scab, and varying 

 degrees of resistance to rusts, powdery mildew and fireblight, are currently 

 available from commercial nurseries. As these cultivars have potential use 

 in apple disease management programs, designed to reduce fungicide usage, we 

 established a block of disease resistant apple cultivars at the Horticultural 

 Research Center in the spring of 1978 to determine their performance in Mass- 

 achusetts. Fruit were harvested in 1982 for the first time. 



Eight cultivars were planted. Prima, Priscilla, and Sir Prize were developed 

 by the Purdue, Rutgers, and Illinois (PRI) Agricultural Experiment Station co- 

 operative apple breeding program. MacFree and Nova Easy-gro were developed in 

 Canada and Liberty and NY61345-2 by the New York Agricultural Experiment 

 Station. Disease-susceptible Imperial Mcintosh was used for comparisons. Trees 

 were obtained from either the New York State Fruit Testing Cooperative or Stark 

 Bros. Nurseries. 



Cultivars used have been described by their developers as follows: 



Prima: 2-1/2 to 3". 60-80% bright red, over yellow ground color. 



Rich flavor and crisp texture, with mild subacid flavor. 

 Flesh, light cream color. Little tendency for fruit to drop 

 before harvest. Fruit matures 1 month before Red Delicious, 

 and will retain its flavor for up to 1 month at 34 F. Trees 

 are spreading and vigorous. Immune to apple scab, susceptible 

 to cedar apple rust, slightly susceptible to powdery mildew, 

 and resistant to fire blight. Excellent dessert apple. 



Priscilla : 2-1/2 to 3". 75-90% bright red, over yellow ground color.. 

 Crisp texture and pleasant aromatic flavor. Texture and 

 flavor maintained for 2-3 months at 34 F. 2 weeks before 

 Delicious (10 days after Prima) . Little tendency for fruit 

 drop before harvest. Trees are moderately spreading and 

 vigorous: terminal growth frequently determinate, ending in 

 a flower bud. Trees and fruit are immune to apple scab, 

 and resistant to cedar apple rust, and fire blight. Fine 

 dessert quality. 



Sir Prize : 3 to 3-1/2". Yellow, russet free. Ripens with Golden 



Delicious (4 weeks after Prima). Juicy flesh, fine grained 

 texture with thin skir^ that is easily bruised with rough 

 handling. Waxy skin does not shrivel in storage. Very good 

 keeping quality through the winter season. Trees are vigorous, 

 triploid and produce an annual crop. Immune to apple scab, 

 moderately resistant to cedar apple rust and powdery mildew, 

 trees have shown little fire blight. Excellent for home 

 planting or use with direct sales or pick-your-own. 



1 9 



Disease Management Technician ^ Extension Technician 



3 Professor of Plant Pathology 



