A precision management approach to monitor apple fruit growth and quality

Absolute and relative fruit growth rates (AGR and RGR) of 5 cultivars were calculated from the oven-dry weights of fruits harvested periodically throughout the growing season. Both AGR and RGR were higher for larger fruit of different cultivars with similar days to maturity, and for summer- versus fall-ripening cultivars. Seasonal variability in AGR and RGR was observed, Apple fruit cortex disks were incubated in 14C-sorbitol solutions in vitro to determine if uptake rates at the cellular level varied between cultivars. Rates of sorbitol accumulation, expressed es μg sorbitol per mg dry weight cortex tissue, declined as the season progressed. Within a cuitivar, uptake rates were not relatad to fruit size, nor were differences found between cortex tissue samples from competing fruit on a spur. Sorbitol uptake rates were significantly lower for the more slowly-growing cultivar. The osmotic potential of the expressed cortex sap, sampled on several dates, was consistently lower for the more rapidly-growing cultivar. Thus, inherent differences in fruit growth rates among cultivars may be due to variation in regulation of osmotic potential.

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Growth Response of Apple Fruit to NAA and Accel: Effect of Intraspur Competition and Position on a Spur

HortScience ◽

10.21273/hortsci.30.4.765d ◽

1995 ◽

Vol 30 (4) ◽

pp. 765D-765

Author(s):

Brent L. Black ◽

Martin J. Bukovac ◽

Matej Stopar

Keyword(s):

Growth Response ◽

Fruit Size ◽

Apple Fruit ◽

Fruit Growth ◽

Crop Load ◽

Commercial Thinning ◽

Whole Tree ◽

Fruit Diameter

Apple fruit size is influenced by position on the spur, and location and number of competing fruits. King fruit appear to have the greatest potential to size and grow best in the absence of intraspur fruit competition (ISFC). Accel (A) and NAA (N), commercial thinning chemicals, influence fruit size beyond their effects on crop load. A 2-year study was conducted to determine the effect of ISFC and position (king, K, or lateral, L) on fruit growth in response to A and N. Branches from `Redchief Delicious' were thinned, after petal fall, to one K, one L, one K + one L, or two L fruits per spur. Whole-tree treatments of N (15 mg·liter–1), A (50 mg·liter–1, 1993; 25 mg·liter–1), and a combination (N+A) were applied at 10-mm king fruit diameter. A nontreated control was included. In 1993, N and N+A reduced fruit size only with ISFC, while A increased fruit size in the absence of ISFC. In 1994, A had no effect, but N and N+A reduced fruit growth with ISFC. In both seasons, A and N decreased the frequency of spurs bearing multiple fruit, while N+A dramatically increased number of spurs with multiple fruits (branch survey).

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Diffuse Flesh Browning in ‘Honeycrisp’ Apple Fruit is Associated with Low Temperatures during Fruit Growth

HortScience ◽

10.21273/hortsci11179-16 ◽

2016 ◽

Vol 51 (10) ◽

pp. 1256-1264 ◽

Cited By ~ 2

Author(s):

Cindy B.S. Tong ◽

Hsueh-Yuan Chang ◽

Jennifer K. Boldt ◽

Yizhou B. Ma ◽

Jennifer R. DeEll ◽

...

Keyword(s):

Detailed Comparison ◽

Apple Fruit ◽

Fruit Growth ◽

Growing Degree Days ◽

Climate Data ◽

Degree Days ◽

Full Bloom ◽

Flesh Browning ◽

Harvest Maturity ◽

Storage Disorders

Multiple types of flesh browning can occur as storage disorders in ‘Honeycrisp’ apple (Malus ×domestica Borkh.) fruit. Predicting its occurrence is hindered by differing definitions of the types of browning, incomplete understanding of their etiologies, and difficulty in assessing harvest maturity of ‘Honeycrisp’ fruit. In 2013, of ‘Honeycrisp’ fruit grown, harvested over multiple weeks, and stored in Maine, Minnesota, Ontario, and Quebec, only the Quebec fruit developed diffuse flesh browning. A detailed comparison showed that the Quebec fruit differed in size, but not in other quality attributes, from fruit of the other locations. The Quebec fruit experienced lower temperatures during active fruit growth and were increasing in cell size up to harvest. Analyses of climate data from 2009 to 2015 indicated that accumulated growing degree-days (GDD) 50–60 day after full bloom (DAFB) could account for 31% of the variation in diffuse flesh browning, and seasonal GDD <500 are associated with a greater likelihood of injury. Fruit that exhibited diffuse flesh browning had higher magnesium and lower fructose levels than unaffected fruit. As these measurements were made after browning was assessed, the timing of the onset of these characteristics in relation to browning cannot be determined.

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Towards understanding the role of temperature in apple fruit growth responses in three geographical regions within New Zealand

The Journal of Horticultural Science and Biotechnology ◽

10.1080/14620316.2000.11511261 ◽

2000 ◽

Vol 75 (4) ◽

pp. 413-422 ◽

Cited By ~ 26

Author(s):

C. J. Stanley ◽

D. S. Tustin ◽

G. B. Lupton ◽

S. Mcartney ◽

W. M. Cashmore ◽

...

Keyword(s):

New Zealand ◽

Apple Fruit ◽

Fruit Growth ◽

Growth Responses ◽

Geographical Regions

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Benzyladenine as A Chemical Thinner for `McIntosh' Apples. II. Effects of Benzyladenine, Bourse Shoot Tip Removal, and Leaf Number on Fruit Retention

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.125.2.177 ◽

2000 ◽

Vol 125 (2) ◽

pp. 177-182 ◽

Cited By ~ 4

Author(s):

Rongcai Yuan ◽

Duane W. Greene

Keyword(s):

Growth Rate ◽

Apple Fruit ◽

Fruit Weight ◽

Shoot Tips ◽

Fruit Growth ◽

Shoot Tip ◽

Soluble Solids ◽

Leaf Number ◽

Solids Concentration ◽

Fruiting Branch

Experiments were conducted to evaluate the effects of BA, removal of bourse shoot tips including only folded leaves and growing point, and different numbers of leaves per fruit on fruit retention and fruit development in `More-Spur McIntosh'/Malling 7 (M.7) apple trees [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.]. Removal of the bourse shoot tip increased fruit retention, whereas BA thinned fruit regardless of whether shoot tips were removed or not. There was no interaction between BA application and shoot tipping. BA thinned fruit only when one leaf per fruit was on a girdled small fruiting branch, but not when leaf number per fruit was two or greater. Fruit weight and soluble solids concentration increased dramatically with increasing leaf number per fruit. BA reduced fruit growth rate when <16 leaves per fruit were present on the girdled branches between 3 and 7 days after treatment, but it did not affect fruit growth rate when 32 leaves per fruit were on the girdled branches. Increasing leaf number also increased viable seed number per fruit while decreasing the number of aborted seeds, but it had no effect on the number of total seeds per fruit. BA reduced the number of viable seeds per fruit only when the number of leaves per fruit was less than four. Results suggest that BA thins apple fruit mainly by reducing carbohydrates available to developing fruitlets. Chemical name used: N-(phenylmethyl)-1H-purine-6-amine [benzyladenine (BA)].

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Cultivar-specific Apple Fruit Growth Rates in Vivo and Sink Activities in Vitro

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.117.3.459 ◽

1992 ◽

Vol 117 (3) ◽

pp. 459-462 ◽

Cited By ~ 5

Author(s):

Douglas D. Archbold

Keyword(s):

Growth Rates ◽

Fruit Size ◽

Apple Fruit ◽

Fruit Growth ◽

Sink Strength ◽

Golden Delicious ◽

Days To Maturity ◽

Physiological Constraint

Absolute and relative fruit growth rates (AGR and RGR) of apple (Malus domestics Borkh.) were calculated from the fruit dry weights of several cultivars harvested periodically following June drop during 1988-90. AGRs were constant or varied slightly, and RGRs generally declined as the season progressed. Generally, both AGR and RGR values were higher for relatively large fruit of several cultivars with similar days to maturity, e.g., `McIntosh' vs. `Jonathan' and for summervs. fall-ripening cultivars, e.g., `Stayman' vs. others. An exception was observed in 1990, when `Golden Delicious' exhibited a higher AGR but lower RGR than `Rome Beauty', yet ripened 1 month earlier. `Golden Delicious' AGR and RGR values were lower for both fruit of a pair on a spur than the values for a single fruit on a spur, and the dominant fruit of the pair exhibited higher growth rates than the inferior fruit. Rates of sorbitol accumulation (SAR) by cortex disks incubated in 14C-labeled sorbitol solutions in vitro declined as the season progressed. Within a cultivar, SARS were not related to fruit size, nor were differences found between cortex disks from competing fruit on a spur, although SARS were higher for both competing fruit on a spur as compared to that of a single fruit per spur. Due to a positive correlation between RGR and SAR values, the SAR of cortex cells may be regulated in such a manner as to be a physiological constraint on fruit sink strength and growth rate.

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REGULATION OF APPLE FRUIT GROWTH RATE BY TURGOR PRESSURE?

HortScience ◽

10.21273/hortsci.27.6.625e ◽

1992 ◽

Vol 27 (6) ◽

pp. 625e-625 ◽

Cited By ~ 1

Author(s):

Douglas D. Archbold

Keyword(s):

Growth Rate ◽

Growth Rates ◽

Osmotic Potential ◽

Turgor Pressure ◽

Apple Fruit ◽

Fruit Growth ◽

Cultivar Differences ◽

Soluble Carbohydrates ◽

Soluble Carbohydrate ◽

Carbohydrate Levels

Maintenance of positive cell turgor is an essential factor in cell, and fruit, expansion. Since apple fruit partition carbohydrates between the starch and soluble pools to maintain turgor, variation among cultivars in this osmoregulatory aspect may play an important role in defining cultivar-specific fruit growth rates. Cultivar-specific apple fruit growth rates were determined over a 6 week period following June drop during 2 seasons. Fruit water relations parameters and carbohydrate levels were also measured. Although cultivar differences were evident, generally, fruit absolute growth rate increased, relative growth rate (RGR) declined, water potential and osmotic potential declined, and turgor potential increased as the season progressed. Soluble carbohydrate levels increased over 6 weeks, while starch levels fluctuated. Soluble carbohydrates contributed 50 to 90% of the osmotic potential. RGR was not correlated to either turgor potential or the relative allocation of carbohydrates between the soluble and starch pools. Thus, although positive turgor was maintained, factors other than turgor per se determine fruit growth rate.

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Reduction of Fruit Load Affects Early Fruit Growth in Apple by Enhancing Carbohydrate Availability, Altering the Expression of Cell Production-related Genes, and Increasing Cell Production

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.138.4.253 ◽

2013 ◽

Vol 138 (4) ◽

pp. 253-262 ◽

Cited By ~ 13

Author(s):

Madhumita Dash ◽

Lisa Klima Johnson ◽

Anish Malladi

Keyword(s):

Fruit Development ◽

Molecular Mechanisms ◽

Apple Fruit ◽

Fruit Growth ◽

Fleshy Fruit ◽

Altered Expression ◽

Cell Production ◽

Carbohydrate Availability ◽

Load Conditions ◽

Fruit Load

Carbohydrate availability is a key factor determining fruit growth in apple (Malus ×domestica) and other fruits. However, the molecular mechanisms regulating fleshy fruit growth in response to changes in carbohydrate availability are not well understood. In this study, carbohydrate availability was manipulated by reducing fruit load, and its effects on apple fruit growth, cell production and expansion, and the expression of genes associated with these processes was investigated. Reduction of fruit load during early fruit development led to a rapid increase in early fruit growth. The increase in fruit growth was associated with a transient increase in sorbitol and fructose concentrations and altered expression of sorbitol dehydrogenase and sucrose synthase genes. Increase in early fruit growth was mediated primarily by an increase in cell production. The aintegumenta gene, MdANT1, an AP2-domain transcription factor associated with the regulation of cell production and fruit growth, displayed an increase in expression by up to 5-fold during early fruit development in response to the reduction in fruit load. Additionally, multiple cell cycle genes positively associated with cell production such as the cyclins, MdCYCA2;1, MdCYCA2;3, MdCYCB1;1, and MdCYCB2;2, and the B-type cyclin-dependent kinases, MdCDKB1;1, MdCDKB1;2, and MdCDKB2;2, displayed higher expression by up to 5-fold under reduced fruit load conditions during early fruit growth. These data indicate that carbohydrate availability affects the expression of key transcription factors and cell proliferation genes, thereby regulating cell production during early fruit growth. Several genes associated with cell expansion such as the expansins, and cobra and cobra-like genes, also displayed altered expression in response to the reduction in fruit load. The expression of three expansin genes was higher under reduced fruit load conditions at maturity, a stage at which a minor increase in cell size was apparent. Together, data from this study indicate that fruit load reduction induces changes in carbohydrate availability and metabolism, which in turn affect cell production-related mechanisms, thereby enhancing early fruit growth.

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