The data also show that spurs bearing fruit with low seed num- 

 bers were more likely to produce a "repeat" bloom. 



The data obtained in 1980-81 (Table 4) show that the 1980 fruit- 

 ing spurs which flowered in 1981 set very few fruits in 1981 in com- 

 parison to the spurs that did not fruit in 1980. This v\?as most 

 noticeable for the Starkrimson strain where only 1% of the 1981 

 "repeat" bloom set fruit whereas 361 of the 1980 non-fruiting spurs 

 possessed apples in 1981. These data indicate that a sizeable 

 proportion of non-fruiting spurs are essential on bearing trees if 

 substantial annual production is to be maintained. 



Summary 



A planting was established in 1964 and 1965 to evaluate the 

 following Delicious strains: Red Prince, Jardine Red, Royal Red, 

 Turner Red, Richared, Rogers Red, Gardiner Red, Sturdeespur, and 

 Starkrimson the last 2 being spur types. The strains have been 

 evaluated through 1980. Leaf N, K, Ca and Mg levels varied among 

 the strains but none was consistently different from another. The 

 cumulative yield per tree from 1970 to 1979 was higher for all stand- 

 ard strains except Red Prince than for the spur strains. Theoretical 

 cumulative yield per acre was highest for Sturdeespur and signifi- 

 cantly higher than all other cultivars with the exception of Turner 

 Red. Sturdeespur had the highest production efficiency. Watercore 

 severity at harvest was inconsistent among the strains, but in 3 

 of 4 years fewer Starkrimson fruits were affected. A sizeable num- 

 ber of non-fruiting spurs are essential each year on bearing trees 

 if substantial annual production is to be maintained. 



********** 



POMOLOGICAL PARAGRAPH 



Publication available . A book entitled "Tree Fruit Growth Regulators" 

 edited by Ronald B. Tukey, Washington State University and Max W. 

 Williams, USDA-SEA-AR, is available for $12 from Growth Regulators, 

 Conference Office, Room 323, AG. Sciences II, Washington State Univer- 

 sity, Pullman, WA 99164. Checks should be made out to Washington State 

 University. This book is a compilation of papers presented at a 

 shortcourse held in February, 1981 on the subject of growth regulators 

 and chemical thinning of deciduous fruit trees. Among the topics dis- 

 cussed are: growth and development of fruit trees, pollination and 

 fruit set, growth regulator and cultural techniques to promote early 

 fruiting of apples, physiological aspects of pruning and training, 

 chemical thinning of apples, and growth regulator uses of tree fruits. 

 This book should be valuable to growers desiring to increase their 

 understanding of fruit trees and of the use and action of plant growth 

 regulators . 



