SEGREGATION AND GENERAL EVALUATION OF SPUR TYPE OR COMPACT GROWTH HABITS IN APPLES

Three orchards consisting of a total of 28,000 apple seedlings, obtained from crosses made from 1971 to 1980, were evaluated for growth type.
Three types were defined: 1) spur characterized by upright and thick growth, short internodes, sparse branching and abundant spurring; 2) compact (non spur) characterized by upright growth, short internodes, frequent branching and less spurring and sometimes more bare wood; 3) columnar characterized by a habit similar to the spur type but with restricted branching and very short internodes with nearly all axillary buds growing into spurs and the tree naturally growing into a sturdy cordon.
Approximately 8% of the seedlings were spur type.
From the cross of two spur types, 30 to 50% were of this type.
From the use of a compact type parent, 20 to 30% of the seedlings were compact.
Less than 0.3% of the seedlings were columnar type.
When both parents were columnar, 44% of the seedlings were of the type.
Factors influencing classification of growth types and possible mode of inheritance are discussed in this paper.

Fruit Breeding and Genetics

J. Blazek

https://doi.org/10.17660/ActaHortic.1992.317.6