Journal APS Oct 2017

CLINE – THINNING PEACHES WITH HIGH-PRESSURE WATER

J ournal of the A merican P omological S ociety

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Table 2. The effect of thinning treatments on commercial grade out of ‘Harrow Beauty’/Bailey peaches in 2008. University of Guelph, Vineland, Ontario. y Table 2. The effect of thinning treatments on commercial grade out of 'Harrow Beauty'/Bailey peaches in 2008. University of Guelph, Vineland, Ontario. y

Weight of fruit (kg)

2.25- 2.4" 57-62 mm 11.2

2.5- 2.74" 63-69 mm

2.75- 2.9" 70-75 mm

3.0- 3.24" 76-81 mm

>= 2.5" 57 mm 35.9 30.8 33.2 28.5

<2.25"

3.25+"

< 57 mm

82+ mm 0.1 0.6 0.1 0.9

Treatment

Hand thinned control

4.8 1.0 1.0 1.3

a b b b

a b b b

16.6 13.2 14.6

a

6.1 9.1 9.6 8.4

1.9 3.7 3.4 6.1

b

Low

4.3 5.6 3.4

ab ab

ab ab

Medium

High

9.6 .

b

a

P value

0.0118

0.0008

0.0170

ns ns

0.0172

0.0421 0.2944

Regression of Low, Med, High z

ns

ns

ns

ns

Q*

ns

y Values within columns not followed by common letters differ at the 5% level of significance, by Tukey's HSD z ns, *, **, ***, indicates not significant, and significant differences at P = 0.05, P = 0.01 and P = 0.001 respectively. y Values within columns not followed by common letters differ at the 5% level of significance, by Tukey's HSD z ns, *, **, ***, indicates not significant, and significant differences at P= 0.05, P=0.01 and P=0.001 respectively.

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 Commercial grade-out of the fruit into seven size categories indicated that all spray treatments increased the weight of fruit in the less than 2 ¼ (57 mm), 2¼ - 2.4“ (57-62 mm), and 2½ -3¾ (63-69 mm) fruit diameter categories (Table 2). Fruit smaller than 57 mm are not sold on the fresh (retail) market in Canada and therefore commercial orchard practices aim to minimize production of fruit in this size category. The LOW, MED, and HIGH treatments resulted in greater weights of fruit in the 3.0-3.24” (76-81 mm) (P=0.01) and ≥ 3.25” (82 mm) (P=0.04) size catego-

ries. Overall, however, no significant treat- ment difference in the weight of fruit in the ≥ 2.5” (58 mm) size category was observed. In 2009, high-pressure water thinning treat- ments had a significant effect on the percent- age of flowers removed for ‘Harrow Beauty’ (P=0.0006) but not for ‘Harrow Diamond’ trees (Table 3). Treatments removed ap- proximately 40 to 57% of flowers, which increased with the time of spraying. Fruit set was also significantly affected for ‘Har- row Beauty’ (P=0.0003) but not for ‘Harrow Diamond’ trees. Fruit set ranged from 25%

CLINE – THINNING PEACHES WITH HIGH-PRESSURE WATER

Table 3. The effect of thinning treatments on flower thinning, fruit set, crop load, tree yield and mean fruit size at harvest of ‘Harrow Diamond’ and ‘Harrow Beauty’ peaches in 2009. Table 3. The effect of thinning treatments on flower thinning, fruit set, crop load, tree yield and mean fruit size at harvest of 'Harrow Diamond' and 'Harrow Beauty' peaches in 2009.

Crop load adjusted mean fruit weight (g)

Final crop load at harvest (frt/cm 2 tcsa)

Percent of flowers removed x,y

Percent fruit set x

Total fruit per tree (number)

Total fruit weight (kg/tree)

Mean fruit weight (g)

Treatment Harrow Diamond Hand thinned control

-

21.5 19.7 19.8 15.6

3.6 4.1 2.6 2.2

168 189 126 113

21.7 24.0 17.7 17.4

153.3 150.1 148.5 147.8

147.4 136.8 155.5 160.1

ab

Low

40.5 45.8 51.6

b a a

Medium

High

P value

0.3327

0.5649

0.2676

0.372

0.4103

0.9109

0.0549

Regression of Low, Med, High z

L*

ns

ns

ns

ns

ns

ns

Harrow Beauty Hand thinned control

-

26.0 38.7 32.7 27.6

c a b

4.3 5.6 3.5 3.7

186 216 145 139

ab

23.7 24.5 18.7 20.1

132.2 125.0 128.8 149.1

b b b a

132.1 116.9 133.5 152.5

b c b a

Low

36.8 48.1 57.0

c b a

a

Medium

ab

High

bc

b

P value

0.0006

0.0003

0.1429

0.0959

0.2589

0.0079

0.0002

Regression of Low, Med, High z

L**

L*

ns

L*

ns

L**

L***

x set was determined on June 17, prior to hand thinning in early July. y Values within columns not followed by common letters differ at the 5% level of significance, by Tujey's HSD Test z ns, *, **, ***, indicates not significant, and significant differences at P= 0.05, P=0.01 and P=0.001 respectively. NE indicates not estimable , l l it le ters di fer at the 5 level of sign ficance, by Tukey's HSD Test z ns, *, **, ***, indicates not significant, and significant differences at P = 0.05, P = 0.01 and P = 0.001 respectively. NE indicates not estima

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