1. Cutting labor and input costs while increasing fruit size, yield and quality, what’s possible and what’s not? Ted DeJong

2. National farm wages have increased by ~100% over 20 years. This may be even higher in California and does not include increased costs related to labor management and reporting.

3. In the same ten year period average US farm fuels expenditures increased by ~59%.

4. Freestone Peach Acreage

5. Cling Peach Acreage

6. Average Freestone Peach Yields Per Acre

7. Average Cling Peach Yields

8. Average Gross Value Per Ton

10. Gross Freestone Peach Returns Per Acre

11. Gross Cling Peach Returns Per Acre

12. Lopez, Johnson and DeJong, California Agriculture, 2007 It is interesting there has been a consistent marketing trend toward packing larger and larger sized fruit over the past 20 years. This has been done by preferentially packing larger sized fruit and discarding more fruit in the small size categories.

14. Simulation of commercial practices Other things being equal, fruit size is inversely related to yield and the relationship is not linear.

15. To make matters worse the previous figure only showed the relationship between average fruit size and yield. Fruit sizes on a tree are normally distributed so there are always some fruit on the tree that will not make size and at higher crop loads a greater proportion of the crop will not make acceptable size.

16. But other things are not always equal. In years with warm springs fruit development rates are more rapid and this means fruit growth rates per day must be greater to make up the same amount of size in a shorter amount of time. This is not possible especially if the fruit are not thinned in time.

17. Thus, fruit size at pit hardening will be smaller and this will very likely carry forward to harvest. The next few slides will demonstrate how this happens. It all follows from the Relative Fruit Growth Model that we have developed for peaches.

18. From Grossman and DeJong 1995

19. If we use the RGR functions shown on the previous slide to project potential fruit dry weight growth for three contrasting seasons we see substantial differences in the timing of potential fruit sink demands for carbon.

20. The differences between seasons is even more apparent when potential absolute fruit growth rates of individual fruits are calculated for the first 50 days after bloom.

21. When the individual fruit growth demands are compounded by pre-thinning crop loads during the first 50 days after bloom, the differences in potential carbon demand by the fruit among years are really apparent. On the other hand, how are the differences in temperature among years like to influence carbon supply to fuel this demand? small + effect on leaf Pn rate min. effect on canopy Pn because of lack of canopy development within 30 dab min. effect on starch mobilization from storage greater competition for CH 2 O from vegetative sinks

22. Taking the art out of pruning and thinning Ted DeJong

23. We have enough understanding to simulate the growth of trees and fruit.

25. What can you do to maintain or optimize yield, fruit size, and fruit quality while minimizing costs Optimize fertilizer and water management Select a good training system and renewal prune to manage fruiting wood and minimize water shoots Select high quality cultivars Reduce crop load and thin early (mechanically (?) combined with hand thinning) Lower tree heights (size-controlling rootstocks and pruning systems) Explore new methods of mechanical harvest

26. We have shown experimentally that early thinning can increase fruit size and yield.

27. Mean fruit dry mass (g fruit -1 ) 6080100120140160180200220240260 10 15 20 25 30 Day of year Unthinned Thinned 90 days after bloom Thinned 60 days after bloom Thinned 30 days after blooom Thinned at bloom 5 We obtain similar results when we use a crop canopy simulation model.

28. Table 1. Fruit yield data from four clingstone peach cultivars in commercial orchards near Kingsburg California that were thinned on two different dates in 1992. Data indicate means +- se for six, four-tree replications per cultivar and thinning date. Adapted from DeJong et al. 1992. Cultivar/Thinning Date Fruit size (gFW/fruit) Crop Load (fruit/tree) Yield (tons/Ha) Loadel 20 March 18 May 113.3 ± 1.4 91.9 ± 2.4 1681 ± 64 1649 ± 40 56.7 ± 2.0 45.3 ± 1.6 Carson 20 March 18 May 127.8 ± 4.7 108.2 ± 2.5 1576 ± 74 1427 ± 53 59.4 ± 2.0 46.0 ± 2.0 Andross 21 March 18 May 123.6 ± 2.1 115.0 ± 1.7 1888 ± 96 1766 ± 58 69.3 ± 2.7 60.8 ± 2.7 Ross 27 March 19 May 163.9 ± 7.0 163.9 ± 3.2 1862 ± 99 1638 ± 69 80.7 ± 2.5 72.2 ± 3.1

29. New approaches to mechanical thinning. The machine on the left is used to reduce flowers at bloom. The machine below is used in New York and is like what is being tested in California now for olive harvesting.

36. Rootstock LoadelFlavorcrest Open VaseKAC-VOpen VaseKAC-V Nemaguard 78.1±0.6854.6±0.9690.2±1.9762.6±1.17 Controller 9 72.2±2.1152.6±2.2186.3±2.5963.4±3.75 Controller 5 53.0±0.3638.1±1.6961.7±1.1841.6±0.39 After 12 growing seasons trees on Controller 9 had trunk circumferences (cm) that were nearly the same as trees on Nemaguard but trees on Hiawatha and Controller 5 were substantially smaller. Trunk circumferences of the KAC-V trees were also smaller than open vase trees. Controlling tree size with rootstocks

37. Differences in vegetative vigor (as reflected by pruning weights) among trees on different rootstocks were apparent very early in the trial and remained fairly consistent. The differences in vigor are essentially the selling points of the size-controlling rootstocks.

38. Rootstock KAC-V LOADELFLAVORCREST Topping Treatment Crop wght/tree (kg) Mean fruit wght (gm) Crop load (#fruit/tr) Fruit wght/TCA (kg/cm 2 ) Crop wght/tree (kg) Mean fruit wght (gm) Crop load (#fruit/tr) Fruit wght/TCA (kg/cm 2 ) Nemaguard Topped 3.3m59.8156.03840.2543.5138.83140.14 Topped 2.4m58.1142.24090.2447.5132.23590.15 Controller 9 Topped 3.3m55.2146.03780.2545.9124.63690.14 Topped 2.4m57.9132.04370.2640.6128.43170.13 Hiawatha Topped 3.3m51.6146.73520.3129.6129.52280.15 Topped 2.4m52.0129.84000.3137.4126.42960.19 Controller 5 Topped 3.3m41.6136.23050.3642.5117.83600.31 Topped 2.4m47.7110.64320.4139.5111.73540.28 Rootstock KAC-V LOADELFLAVORCREST Topping Treatment Crop wght/tree (kg) Mean fruit wght (gm) Crop load (#fruit/tr) Fruit wght/TCA (kg/cm 2 ) Crop wght/tree (kg) Mean fruit wght (gm) Crop load (#fruit/tr) Fruit wght/TCA (kg/cm 2 ) Nemaguard Topped 3.3m59.8156.03840.2543.5138.83140.14 Topped 2.4m58.1142.24090.2447.5132.23590.15 Controller 9 Topped 3.3m55.2146.03780.2545.9124.63690.14 Topped 2.4m57.9132.04370.2640.6128.43170.13 Hiawatha Topped 3.3m51.6146.73520.3129.6129.52280.15 Topped 2.4m52.0129.84000.3137.4126.42960.19 Controller 5 Topped 3.3m41.6136.23050.3642.5117.83600.31 Topped 2.4m47.7110.64320.4139.5111.73540.28 Rootstock KAC-V LOADELFLAVORCREST Topping Treatment Crop wght/tr (kg) Mean fruit weight (gm) Mean crop load (#fruit/tr) Fruit wght/TCA (kg/cm 2 ) Crop wght/tr (kg) Mean fruit weight (gm) Mean crop load (#fruit/tr) Fruit wght/TCA (kg/cm 2 ) Nemaguard Topped 3.3m59.8156.03840.2543.5138.83140.14 Topped 2.4m58.1142.24090.2447.5132.23590.15 Controller 9 Topped 3.3m55.2146.03780.2545.9124.63690.14 Topped 2.4m57.9132.04370.2640.6128.43170.13 Controller 5 Topped 3.3m41.6136.23050.3642.5117.83600.31 Topped 2.4m47.7110.64320.4139.5111.73540.28 OPEN VASE Nemaguard Topped 3.3m117.9148.47950.2488.4143.96140.14 Topped 2.4m88.7175.25060.1878.2146.65340.12 Controller 9 Topped 3.3m102.2124.98180.2584.9116.87270.14 Topped 2.4m85.0142.56000.2072.0113.76330.12 Controller 5 Topped 3.3m86.76122.07110.3883.4120.56920.27 Topped 2.4m89.09125.07130.3961.4118.65180.20

39. Bottom line: But, based on the knowledge that we now have, I don’t see how it will be possible to substantially increase profitability of producing fresh market peaches, nectarines and plums in California without some strategic restructuring of the industry to increase the value of the fruit that is sold. For processing peaches I believe you have the possibility to increase profitability if you concentrate on restructuring the orchards to decrease thinning and harvest costs while continuing to optimize all other management inputs and putting pressure on buyers for increases in price paid for your fruit.

40. Thanks for your attention! Questions?

41. Gross Freestone Peach Returns Per Acre

42. Cling Peach Acreage

43. Average Cling Peach Yields

44. Gross Cling Peach Returns Per Acre