SJVAR&EC

Report Nximber 4 - 1981

HARRY L. ANDfilSReduction of Post-Harvest Shatter in

.Table Thompson Seedless

Fred Jensen, Extension Viticulturist, EarlierDon Luvisi, Farm Advisor, Kem CountyBob Beede, Farm Advisor, Kings County

Larry Bettiga, Staff Research Associate, Earlier

Summary

A standard double berry-enlarging gibberellin spray applied

at fruit set and fruit set plus one week was compared to a delayed

single spray applied one week after fruit set. The berry weights

with the delayed treatment were nine percent lower than the double

spray while the number of berries that shattered was reduced about

thirty-seven percent.

When field packed and vibrator packed boxes were compared,

the vibration pack reduced the number of berries that shattered by

forty-five percent.

A comparison of gibberellin bloom treatments applied as single

10 or 20 ppm concentrations or as two 10 ppm concentrations showed

no differences in shatter.

Several growth regulators applied with the gibberellin berry

enlargingspray failed to reduce shatter. Some slightly increased

berry weight.

In 1980 trials, post-harvest shatter was significantly reduced when

the berry-enlarging gibberellin spray was delayed for one week after fruit

set. However, this delay also resulted in smaller berries. Some of

these treatments were repeated in 1981 with the fruit packed by two methods,

normal place packing by hand and also field vibration pack.

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- The effects of the bloom gibberellin thinning sprays on shatter

had not previously been determined. Single and double gibberellin

sprays were compared.

Several plant growth regulators were tested as to their effects in

reducing shatter. These were added to the berry-enlarging gibberellin

treatment applied at fruit set.

Methods

A. Gibberellin Bloom-Thinning Trial

The trial wa~s located in a vineyard at Delano. The trial was designed

as a randomized complete block with eight replications of 10 vines and

three treatments. The sprays were applied with a single row inverted "U"

boom at a rate of about 200 gallons per acre. The girdling, thinning,

and berry-enlarging gibberellin sprays were those practices normally

used by the grower. However due to error, half of the rows did not receive

any berry-enlarging gibberellin. This resulted in those treatments having

berry weights 28% lower than the sprayed rows.

The effects of the treatments in reducing set was assessed by counting

the number of berries per centimeter of shoulder length on 15 shoulders

from each replication. The second shoulder from the base of the cluster

was chosen»for this determination.

One box, 23 pounds net, was picked and packed from each replicate.

This box was taken to a cool room, about 60°F, for temperature stabilization.

The next day, it was vibrated for 20 seconds, inverted, and the loose

berries counted and weighed.

B, Time of Application of Berry-Enlarging Gibberellin Spray

The trial was located in a vineyard at Delano. Each replication

consisted of ten vines. The design was a randomized complete block with

eight replications of the two treatments. The gibberellin sprays were

-3- SJVAR&ECReport Number 4 - 1981

applied with an inverted "U" boom at a rate of 200 gallons per acre.

The berry diameters were as follows:

PredominantGibberellin, ppm- Date diameter, mm Average diameters, mm

1. 40 ppm May 27 4-6 4.6

40 ppm June 3 7-9 7.9

2. 100 ppm June 3 6-8 7.0

-The bloom sprays, girdling and thinning operations were those normally

used by the grower.

Samples consisted of 200 berries per replication,

C. Plant Growth Regulators Combined with Gibberellin Berry Enlarging

Sprays,

Because most of the plant growth regulators tested were not registered

for use, this trial was located at the Kearney Field Station near Parlier.

The design of the trial was a randomized complete block. There were four

vines per replication and four replications per treatment. The vines were

treated on May 14 at about 75% bloom with a 10 ppm gibberellin spray.

The growth regulators were added to the fruit set gibberellin treatments

applied on May 28, when the predominant berry diameter was 5-6 mm.

The plant growth regulators used were:

Common Name Trade Name Chemical Name

Daminozide Ala:^^ Succinic acid 2,2 dimethyIhydrazide

6 BA None 6-benzylamino purine

pCPA None Para-chlorophenoxyacetic acid

3

GA^ y None A mixture of gibberellins 4 and 7

mepiquat Pix^ N-N-dimethylpiperidinium chloridechloride

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Report Number 4 - 1961

The vines in the trial were trunk girdled on May 29 and 30 and the

clusters tipped on June 1. The numbers of clusters were not reduced

because of the light crop.

Berry samples, consisting of 200 berries, were taken on August 26.

One box, 23 pounds net, was packed from each replication by one packer on

August 27. The boxes were then carefully inverted and the shattered

berries counted and weighed.

Results

A. Gibberellin Bloom Thinning Trial

The results of this trial are given in Table 1. There were no

significant differences in fruit set, soluble solids or acidity from the

field samples. When packed, there were no differences in amount of shatter.

B. Time of Application of Berry-Enlarging Gibberellin Spray

The results of this trial are given in Table 2. The single delayed

100 ppm gibberellin spray significantly reduced berry size and amount of

shatter as compared to the double spray, 40 ppm + 40 ppm. The berries

in the single application delayed spray exhibited a slight amount of berry

discoloration while none was noted with the double spray. There was no

difference in the amount of water berries between the two treatments.

The fruit in this trial was packed both by hand place pack and by

vibration. With vibration, the box was loosely filled to a 23 pound net

weight. A light pressure was then applied on the lid while the box was

vibrated for twelve seconds at three gravity acceleration.

The vibration pack reduced numbers of berries that shattered by 45%

and the weight of shattered fruit per box by 43%. These results are shown

in Table 3. The factorial analyses from which this information was

extracted for Tables 2 and 3, are given in Tables 4 through 7.

-5- SJVAR&EC

Report Number 4 - 1981

The vibrator pack was not quite as even as the place pack. Other

than that, there were no differences until the boxes were inverted. At

that point, it became evident that the vibration pack had less shatter

than the place pack,

C, Plant Growth Regulators Combined with Berry EnlargingGibberellin

Sprays.

The results of the trial are giiyen in Table 7. The berry weight was

increased by 6BA at 10 to 25 ppm, and by pCPA as compared to GA^ alone.There were only a few significant differences in soluble solids and titrat-

able acidity. The shatter, either number of berries or weight, after packing

did not show any significant differences between treatments.f

The fruit treated with 6BA, at either 10 or 25 ppm, could be recognized

because of their slightly larger berries but primarily because of their

distinctive appearance.

GA^ used for both bloom thinning and berry-enlarging treatment,was not different from GA^. The bloom thinning response was observed butnot measured. Observation of the fruit indicated no benefit of GA, _4-7

over GA^,

Discussion

The shatter in 1981 was not nearly so severe as in 1980, In 1980,

up to four pounds of shatter per box was obtained in some of the trials.

In 1981, the maximum shatter was about a pound and a half per box,

- -The most promising method of reducing shatter appears to be vibration

packing. The vibration pack reported herein reduced shatter by nearly

50 percent, A 1975 trial showed shatter could be reduced up to 70% by

using vibration pack instead of a place pack. Methods must be worked out

to make field vibration packing feasible if growers show interest in this

method.

-6- SJVAR&EC

Report Number 4 - 1981

- - Uhi 1Pidelaying rhe application of i;he iberry-enlargin gibberellin

is^rays^ for-a week past fruit set does^reduce shatter, the loss of some

= r #bexry weight, the possiblility of. berry discoloration and increased

. :-Mia±er-berries diminishes the. appeal mf :this treatment,

c. fEhe trials rusing plant regulators with the gibberellin enlarging

streatments did.not.reveal.any.promising materials.

Table 1, A comparison of single and double gibberellin bloom thinning sprays on fruit characteristicsand shatter of Thompson Seedless

Field Samples , August 13 Field Packed Fruit, August 14Bloom

Gibberellin,1st

ppm2nd

No. of berries

per cm ofshoulder length °Brix

Titratable

acidity

No. of shatteredberries per

box

Weight ofshattered berries

per box, grams-

BerryWeightgrams *^Brix

- 10 3.00a^^ 20.4a .49a 132a 584a 4.29a 20.9a

10 10 3.19a 20.6a .48a 120a 503a 4.07a 21.1a

20 3.15a 20.4a .49a 140a 582a 4.11a 20.8a

2J Mean separation with Duncan*^ Multiple Range Test, 5% level.

Note; Due to error, only 3 checks of no treatment were left out of 8 treatments. These 3 could not be included

in the analysis. The average of bloom checks was 4.16 berries per cm. of shoulder length. Apparently

set was reduced about 25% by any of the bloom treatments.

iTabie 2. : The efl^ect isf :time .of sapplication of gibberellin berry-enlarging treatments

i)n ifrnit-characteristics of Thompson Seedless,

'

"- Field Samples, August 13 Field Packs, August 14Gibberellin Cone, ppm. Berry weight Titratable No. of shattered Weight of shatteredMay 27 June 3 grams Brix Acidity berries per box berries per box, gm.

40- .40 5..24a 19.8a .53a 140a 726a

0 riOO 4;7-9b 20.7b .58b 88b 362b

Table 3. The effect of type of field pack on shatter, August 13.

No. of shattered Weight of shattered'iType of Pack -berries per box berries per box, gms

Place pack 146a 693a

Vibration pack 81b 395b

Table 4. The effect of gibberellin treatment and packing method on number of shattered

berries per box.

GibberellinTreatment Packing Method

Hand Vibration

Average effectgibberellin

40 + 40

0 + 100

176

116

103

59

140

88

^Average effect. ^crf-packing

146 81

LSD .05 Gibberellin = 27, Packing =27, Interaction = NS

Table 5. Thfe effect of gibberellin. treatment and packing method on weight of

shattered fruit per box, grams.

Gibberellin Packing Method Average effecttreatment Hand Vibration of gibberellin

40 -h 40 905 546 726

0 + 100 481 243 362

Average effect 693 395of packing

LSD e05 Gibberellin = 128, Packing = 128, Interaction - NS

Table 6. The effect of gibberellin treatment and packing method on berry weight,

grams of shattered berries.

Gibberellin Packing Method Average effecttreatment Hand Vibration of gibberellin

40 + 40 5.19 5.21 5.20

0 + 100 4.14 4.16 4.15

Average effect 4.67 4.68of packing

LSD .05 Gibberellin = 0.25, Packing = NS, Interaction = NS

Table 7, The effect of gibberellin treatment and packing method on soluble solidsoBrix, of shattered berries.

Gibberellin Packing Method Average effecttreatment Hand Vibration of gibberellin

-40 + 40 19.9 19,8 19.8

0 + 100 20.5 21.2 20.8

Average effect 20,2 20.5of packing

LSD .05 Gibberellin - .05, Packing = NS, Interaction = NS

Table 8. The effect of several growth regulators on fruit characteristics and post-harvest shatter of Thompson

Seedless.

Treatment Packed Fruit, August 27Field Samples, August 26 Berry Wt. of

Fruit Set Spray Titrat- if Shattered Wt. Shattered shattered

Bloom Spray GibberellinAdditional

growth regulatorWt./berry

gms.^Brix

ableAcidity

berries perbox

berries perbox, gms,

berries

gms.

1. GA^ 10 ppm GA3 100 ppm None A.66ab 21.2c .50b 69a 30Aa A. 39a

2. " >1 II II Ala^85, h lb/100 A.7Aabc 20.3bc «A6a 109a A79a A. 32a

3. " It II " " 1 lb/100 A.72abc 19.7ab . A6a 75a 358a A. 2Aa

A. " It II II 6BA, 10 ppm 5.06bc 19.6ab .A9ab 9Aa A18a A.A6ab

5. " It II II " 25 ppm A.9Abc 19.Aab . A8ab 87a AlAa A.75ab

6. " II II II " 50 ppm A.81abc 19.2ab . A8ab 99a A29a A.A2a

7. " II II II ^^CPA, ppm 5.26c 19.6ab .A9ab A3a 212a 5.08b

8. " II II II PiJ^l pt/100c * (

A.76abc 18.6a . A9ab 89a 390a A.A2a

9. " II It " II ' A.61ab^ i 1

19.8ab .50b 95a A28a! "

A.A6ab

10. OA,' A- 7 PPS 100 ppm1 I r f.;'.

None A. 39a 19.8ab .50b 80a A. 09a