Improving fruit size and packout of Late Valencia oranges with ethephon fruit-thinning sprays

Hutton, RJ

doi:10.1071/ea9920753

Cited by 7 publications

(6 citation statements)

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“…The relationship between temperature and Brix (Fig 2) varied considerably from one season to the next, so the general relationship between Brix and EHUs would not be a reliable predictor of fruit sweetness. There is nothing in the climatic or laboratory data that gives any indication of the reasons for this variation, but alternate light and heavy cropping cycles 21 would largely explain the variation in recorded Brix levels for similar EHU values across seasons in the same locations. The results indicate that the processes causing changes in total soluble sugars in oranges are not strongly affected by temperatureÐan indication that should be investigated in much more detailed studies.…”

Section: Discussionmentioning

confidence: 91%

Temperature sums experienced before harvest partially determine the post-maturation juicing quality of oranges grown in the Murrumbidgee Irrigation Areas (MIA) of New South Wales

Hutton¹,

Landsberg

2000

J. Sci. Food Agric.

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Section: Discussionmentioning

confidence: 91%

Temperature sums experienced before harvest partially determine the post-maturation juicing quality of oranges grown in the Murrumbidgee Irrigation Areas (MIA) of New South Wales

Hutton¹,

Landsberg

2000

J. Sci. Food Agric.

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“…Crop load management by chemical or manual removal of blossoms or fruit has been shown to improve fruit quality in peach (Farley, 1923), wine grapes (Weaver and Pool, 1971), apple (Greene et al, 1990), plum (Wells and Bukovac, 1978), and oranges (Hutton, 1992). Traditionally, sweet cherry crop loads are managed indirectly, by annual pruning to control vegetative growth and thereby, future fruiting sites.…”

mentioning

confidence: 99%

`Bing' Sweet Cherry on the Dwarfing Rootstock `Gisela 5': Thinning Affects Fruit Quality and Vegetative Growth but not Net CO2 Exchange

Whiting¹,

Lang²

2004

jashs

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ADDITIONAL INDEX WORDS. carbohydrate assimilation, fruit to leaf area ratio, photosynthesis, Prunus avium, sink strength, yield ABSTRACT. Canopy fruit to leaf area ratios (fruit no./m 2 leaf area, F:LA) of 7-and 8-year-old 'Bingʼ sweet cherry (Prunus avium L.) on the dwarfi ng rootstock 'Gisela 5ʼ (P. cerasus L. x P. canescens L.) were manipulated by thinning dormant fruit buds. F:LA infl uenced yield, fruit quality, and vegetative growth, but there were no consistent effects on whole canopy net CO 2 exchange rate (NCER canopy ). Trees thinned to 20 fruit/m 2 LA had yield reduced by 68% but had increased fruit weight (+25%), fi rmness (+25%), soluble solids (+20%), and fruit diameter (+14%), compared to unthinned trees (84 fruit/m 2 ). Fruit quality declined when canopy LA was ≈200 cm 2 /fruit, suggesting that photoassimilate capacity becomes limiting to fruit growth below this ratio. NCER canopy and net assimilation varied seasonally, being highest during stage III of fruit development (64 days after full bloom, DAFB), and falling more than 50% by 90 DAFB. Final shoot length, LA/spur, and trunk expansion were related negatively to F:LA. F:LA did not affect subsequent fl oral bud induction per se, but the number of fl owers initiated per bud was negatively and linearly related to F:LA. Although all trees were thinned to equal fl oral bud levels per spur for the year following initial treatment (2001), fruit yields were highest on the trees that previously had no fruit, refl ecting the increased number of fl owers initiated per fl oral bud. Nonfruiting trees exhibited a sigmoidal pattern of shoot growth and trunk expansion, whereas fruiting trees exhibited a double sigmoidal pattern due to a growth lag during Stage III of fruit development. Vegetative growth in the second year was not related to current or previous season F:LA. We estimate that the LA on a typical spur is only suffi cient to support the full growth potential of a single fruit; more heavily-set spurs require supplemental LA from nonfruiting shoots. From these studies there appears to be a hierarchy of developmental sensitivity to high F:LA for above-ground organs in 'Bingʼ/ʼGisela 5ʼ sweet cherry trees: trunk expansion > fruit soluble solids (Stage III) > fruit growth (Stage III) > LA/spur > shoot elongation > fruit growth (Stages I and II) > LA/shoot. Current season F:LA had a greater infl uence on fruit quality than prior cropping history, underscoring the importance of imposing annual strategies to balance fruit number with LA.

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“…As citrus fruitlets developed after bloom, sensitivity to ethephon was high and variable from year to year but decreased as growth continued. Ethephon concentrations up to 400 mgÁL -1 applied during Response Period I reduced fruit number in ''on-crop'' years, but unpredictable fruitlet removal and intense defoliation prevented its wide-scale use as a thinning agent in citrus-growing areas where thinning is needed (Gallash, 1974;Hutton, 1992;Kender et al, 2000). Young citrus fruitlets behave as climacteric fruit with System II-like autocatalytic ethylene biosynthesis activity (Katz et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Organ Loss and Yield Impacts of ‘Valencia’ Sweet Orange in Response to Fruit Abscission Agents

Pozo¹,

Burns²

2009

horts

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To successfully use abscission agents for ‘Valencia’ sweet orange mechanical harvesting throughout the harvest season, unwanted flower, fruitlet, and leaf drop must be assessed and minimized. Ethephon (400 mg·L−1), 1-methylcyclopropene (1-MCP; 5 mm), ethephon + 1-MCP, 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP; 200 mg·L−1), and a kinetic adjuvant control [0.15% (v/v)] were applied to ‘Valencia’ branches at various times from full bloom in Mar. 2006 to the end of full bloom in Mar. 2008. Effects of these treatments on fruit detachment force (FDF) and abscission of developing and mature fruit, flowers, and leaves were recorded. Three separate response periods to abscission agent applications were observed: the first spanned the first 100 days after bloom (DAB) and was characterized by high initial response followed by decreasing sensitivity; the second spanned between 100 and 225 DAB and was characterized by little to no response; and the third spanned from 225 DAB to harvest and was characterized by a gain in sensitivity. Young fruitlets in the first response period were highly sensitive to ethephon but were less sensitive to CMNP or ethephon + 1-MCP. Mature fruit in the third response period were highly sensitive to CMNP and less sensitive to ethephon or ethephon + 1-MCP. The application of ethephon resulted in high leaf abscission and showed no clear sensitivity pattern throughout both cropping years. CMNP or ethephon + 1-MCP application caused minimal leaf abscission. The same abscission agent treatments were applied on whole tree canopies 6 and 28 DAB in Mar. 2007. Application date had no significant effect on the measured parameters. Although ethephon application induced high initial leaf drop, leaf area indices determined 7 months after any compound application were not significantly different. However, subsequent 2008 yield in trees sprayed with ethephon in 2007 was significantly less, whereas 2008 flower number was higher. The results indicate a complex interaction of fruitlet abscission and leaf loss during the first response period contributed to yield reduction and increased flower number in ethephon-treated trees.

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Improving fruit size and packout of Late Valencia oranges with ethephon fruit-thinning sprays

Cited by 7 publications

References 0 publications

Temperature sums experienced before harvest partially determine the post-maturation juicing quality of oranges grown in the Murrumbidgee Irrigation Areas (MIA) of New South Wales

Temperature sums experienced before harvest partially determine the post-maturation juicing quality of oranges grown in the Murrumbidgee Irrigation Areas (MIA) of New South Wales

`Bing' Sweet Cherry on the Dwarfing Rootstock `Gisela 5': Thinning Affects Fruit Quality and Vegetative Growth but not Net CO2 Exchange

Organ Loss and Yield Impacts of ‘Valencia’ Sweet Orange in Response to Fruit Abscission Agents

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