William Peacock 1, Joe Smilanick 2 and Carmen Gispert 3. 1, 3 University of California, Cooperative Extension 2. USDA-ARS Parlier

Transcription

1 William Peacock 1, Joe Smilanick 2 and Carmen Gispert 3 1, 3 University of California, Cooperative Extension 2 USDA-ARS Parlier

2

3

4 Challenges of Table Grape Production in the Desert Mild temp during the dormant period can affect vine development Delayed or erratic bud break Uneven maturity Need of plant growth regulators to enhance color

5 Scarlet Royal Large (0.8 kg./1.8 lb.), conical-shaped clusters Oval shape berries about 5-7 grams Flesh firm and meaty and the skin is medium to thick Sweet and neutral flavor In 2014 represented 9.5% of the total crop

6 GA and Girdling Initially ppm of GA at 40-60% Now ppm 20 ppm at fruit set for berry size No detrimental effect if girdled

7

8 Applications of Foliar K Common practice in California Previous work of Smilanick and Hashim showed that when applied after veraison increases SS, berry firmness, and color of red varieties

9 Regulated Deficit Irrigation on Table Grapes It advances color and soluble solids Promising approach to manage maturity specially when a applied at the onset of veraison In this work we evaluated the interaction of deficit irrigation with PGR s, foliar K, and girdling on fruit characteristics of Scarlet Royal grown in the desert region of California

10 Deficit Irrigation The primary purpose of deficit irrigation during fruit ripening is to slow shoot growth. The shoot tip is a strong sink for photosynthates and slowing shoot growth during ripening enhances the flux of carbohydrates to fruit. The amount of stress to apply to maximize fruit maturity while minimizing negative impacts on fruit size and vine capacity is not entirely understood.

11 Randomized Split Plot Design 2013 Factor A Irrigation Factor B Foliar K Factor C PGR s 1. Full 1. Control 1. Control 2. Deficit 2. K at 14 Brix (9.4 L per ha) 2. Ethephon (2.4 L per ha) 3. ABA (375 g per ha) 4. Girdle

12 Scarlet Royal Mecca Treatment Effects on Harvest Harvest Date: July 1, 3013 Treatments Crop Load Total Picked Irrigation Foliar K PGR (Pounds per Vine) (%) Full No K Control % Ethrel % ABA % Girdle % Yes K Control % Ethrel % ABA % Girdle % Deficit No K Control % Ethrel % ABA % Girdle % Yes K Control % Ethrel % ABA % Girdle % L.S.D. 05 n.s. 4.0

13 Results Deficit irrigation increased harvestable fruit from 6% to 12%. Deficit irrigation plus foliar potassium increased harvestable fruit from 6% to 24%. The most effective deficit irrigation treatment was foliar potassium plus ethephon which increased harvestable fruit from 6% to 35%. There are physiological interactions that are occurring that would be interesting to elucidate in the future.

14 Summary Deficit irrigation during fruit ripening, beginning at the lag phase and continuing through harvest, enhanced both color and sugar maturity - compared to vines fully irrigated during ripening. There was a positive interaction between foliar potassium and deficit irrigation and this combination increased harvestable fruit from 6% to 24% of the total crop load. The most efficacious treatment was deficit irrigation in combination with both potassium and ethephon which increased the harvestable fruit from 6% to 35%

15 Control with K

16 Girdle

17 Protone no K

18 Ethrel with K

19 No Cultural Fully Irrigated

20 Cultural plus Deficit irrigation until harvest

21

22 Thank you!

23 Plot Design Control 2. Cultural Canopy No Foliar K Foliar K 3 quarts/ac No Ethrel Ethrel 1 pint/ac No Girdle Girdle Irrigation 1. Full during ripening until harvest 2. Deficit after veraison until harvest For 9 days For 17 days Until harvest

24 Influence of irrigation and cultural treatments on fruit characteristics Treatments Sugar B. Wt. B. Length B. Width Firmness Irrigation Cultural (brix o ) (g) (mm) (mm) (g) Cultural Full Irrigation 17.4 a 6.0 a 28.6 a 19.8 a a 9 day deficit 18.6 b 6.2 a 27.2 a 19.0 a a 17 day deficit 18.4 b 6.3 a 27.9 a 18.9 a a 27 day deficit 18.5 b 5.8 a 26.9 a 19.0 a a Grower Schedule 19.0 b 6.4 a 27.7 a 19.8 a a Avg. over irrigation Control 18.1 a 5.5 a 26.1 a 18.5 a a Cultural 18.4 a 6.1 b 27.7 b 19.3 b a 1. Cultural: Foliar K + Ethrel + Girdle all applied early veraison.

25 Influence of irrigation and cultural treatments on fruit characteristics Treatments Table 2. Influence of Sugar irrigation and cultural B. Wt. treatments B. on Length fruit characteristics. B. Width Firmness Irrigation Cultural (Brix o ) (g) (mm) (mm) (g) Full Irrigation Control 16.7 a 5.5 a 25.9 a 18.6 a a 9 day deficit 18.3 b 5.6 a 27.0 a 18.6 a a 17 day deficit 18.2 b 5.5 a 25.2 a 18.1 a a 27 day deficit 19.0 b 5.2 a 26.4 a 18.3 a a Grower Schedule 18.3 b 5.5 a 26.4 a 18.6 a a 1. Cultural: Foliar K + Ethrel + Girdle all applied early veraison.