50 



40- 





o 30- 



CM 



Al 



CO 



o 



o 



CO 



20 



10 



Top 



tions) of six trees each. 

 In mid-March, 12 buds 

 of similar size and lo- 

 cation were selected 

 and marked with 

 white paint. The 

 marked buds on one 

 tree in each group 

 were notched on 

 March 31, April 11, 

 April 23, May 8, or 

 May 22, about six, 

 four, or two weeks be- 

 fore anticipated full 

 bloom, at full bloom, or 

 two weeks after full 

 bloom, respectively. 

 Trees reached silver 

 tip on April 4, green tip 

 on April 10, and 1/2- 

 inch green on April 23. 

 Buds on one tree per 

 replication were not 

 notched and served as 

 the control. After 

 leaves dropped in November, all marked buds or 

 shoots were measured and the numbers of buds 

 with shoots two inches or longer were recorded. 

 Clearly, the optimum period of notching was 

 between two and four weeks before full bloom 

 (Figure 2). Notching done before or after this 

 time was less effective. We speculate that the 

 effectiveness of early notching was diminished 

 because the wound healed before significant 

 growth occurred, and the inhibitory effects of the 

 apical buds on lateral bud growth were reestab- 

 lished. We believe that late notching was less 

 effective because once growth starts in the 

 spring, the potential for an inhibited bud to grow 

 is reduced. The longer notching is delayed, the 

 less effect notching will have. The window for 

 the most effective period for notching is rather 

 narrow. 



Position of Bud: Top vs Side vs. 

 Bottom of a Branch 



In 1987, twenty Spigold/M.7 trees were se- 

 lected and paired into 10 groups (replications). 



I Control 

 I Notched 



Side 



Bottom 



Bud position 



Figure 3. The effects of bud position (top, side, or bottom of branch) 

 on shoot growth with or without notching. Data represent the 

 percent of marked buds. This experiment was conducted in 1987 on 

 Spigold/M.7. 



Ten buds each were selected randomly on the 

 top, side, and bottom of one-year-old portions of 

 scaffold limbs. All marked buds on one of the two 

 paired trees were notched on April 22 (2.5 weeks 

 before full bloom). Marked buds on the second 

 tree in each group were not notched, and served 

 as the control. The lengths of all marked buds 

 were measured after leaf drop in November. 



Notching was most effective at inducing 

 shoot growth from buds on the top of a branch, 

 intermediately effective from buds on the side, 

 and least effective from buds on the underside of 

 a branch (Figure 3). This response generally 

 reflects the normal relationship of shoot growth 

 from buds in these positions; however, notching 

 enhanced that shoot growth dramatically. 

 Rarely would one choose to have a bud on the top 

 of a scaffold develop a shoot, because it would be 

 vigorous and unproductive. Even if desired, 

 very few buds on the lower side of a branch will 

 grow after being notched. Therefore, if lateral 

 branching is desired on scaffolds, notching 

 should be confined to buds on the sides of those 

 branches. 



Fruit Notes, Winter, 1992 



11 



