Abstract
Over 3 years (2016–18), tree productivity, biennial bearing, return bloom, and fruit quality were evaluated for seven high-tannin cider apple ( Malus ×domestica Borkh.) cultivars. Five treatments were evaluated on each of the seven cultivars: hand-thinned of all fruit (a zero crop load treatment); hand-thinned to crop densities of three, six, or nine fruit/cm 2 trunk cross-sectional area (TCSA); or left unthinned. In this paper, we report on the fruit maturity and juice quality properties that were analyzed for the three nonzero crop load treatments and the unthinned control. The effects of crop load on fruit maturity, as measured by starch pattern index and preharvest drop, were cultivar dependent. Crop density (fruit/cm 2 TCSA) had a significant effect on all fruit maturity and juice quality variables, although effects were weakest in the “off” year (2017) for the whole planting when initial fruit set was low. As crop density increased, total poly phenols, titratable acidity, soluble solids, and primary amino nitrogen decreased in the juice of all seven cultivars. A partial budget analysis indicated that the reduced costs of nitrogen supplements due to increased primary amino nitrogen concentration alone would not justify cost of chemical or hand-thinning. By extrapolating the spring flowering density in the fourth year to potential fruit yields at harvest, we found that reducing crop load was projected to increase cumulative total polyphenol yields per tree over the long term. For the cultivars in this experiment, a target crop density of nine fruit/cm 2 was found to adequately decrease biennial bearing while also not diminishing juice quality for hard cider production. High-tannin cider apple growers should consider juice quality, particularly tannin production, when making crop load management decisions.
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Claims 7
Claim · model-written summary
Crop load effects on starch index and preharvest drop depended on cultivar.
- Taxon
- apple
Malus domesticae1 - Treatment
- crop loade0
- Outcome
- fruit maturitye0
- Qualifier
- cultivar dependente0
Not reportedComparatorDirectionValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects of crop load on fruit maturity, as measured by starch pattern index and preharvest drop, were cultivar dependent”
e1“cider apple ( Malus ×domestica Borkh.) cultivars”
Claim · model-written summary
Crop density significantly affected all maturity and juice quality variables.
- Taxon
- appleMalus domesticae1
- Treatment
- Crop densitye0
- Outcome
- fruit maturity and juice quality variablese0
Not reportedComparatorDirectionValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crop density (fruit/cm 2 TCSA) had a significant effect on all fruit maturity and juice quality variables”
e1“cider apple ( Malus ×domestica Borkh.) cultivars”
Claim · model-written summary
Increasing crop density decreased total polyphenols and titratable acidity in juice.
- Taxon
- appleMalus domesticae1
- Treatment
- crop densitye0
- Outcome
- total poly phenols, titratable aciditye0
- Direction
- decreasede0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As crop density increased, total poly phenols, titratable acidity, soluble solids, and primary amino nitrogen decreased in the juice of all seven cultivars”
e1“cider apple ( Malus ×domestica Borkh.) cultivars”
Claim · model-written summary
Increasing crop density decreased soluble solids and primary amino nitrogen in juice.
- Taxon
- appleMalus domesticae1
- Treatment
- crop densitye0
- Outcome
- soluble solids, and primary amino nitrogene0
- Direction
- decreasede0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As crop density increased, total poly phenols, titratable acidity, soluble solids, and primary amino nitrogen decreased in the juice of all seven cultivars”
e1“cider apple ( Malus ×domestica Borkh.) cultivars”
Claim · model-written summary
Lower nitrogen supplement costs from higher amino nitrogen alone did not justify thinning costs.
- Taxon
- appleMalus domesticae1
- Outcome
- costs of nitrogen supplementse0
- Direction
- reducede0
Not reportedTreatmentComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduced costs of nitrogen supplements due to increased primary amino nitrogen concentration alone would not justify cost of chemical or hand-thinning”
e1“cider apple ( Malus ×domestica Borkh.) cultivars”
Claim · model-written summary
Reducing crop load was projected to raise long-term total polyphenol yield per tree.
- Taxon
- appleMalus domesticae1
- Treatment
- reducing crop loade0
- Outcome
- cumulative total polyphenol yields per treee0
- Direction
- increasee0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reducing crop load was projected to increase cumulative total polyphenol yields per tree over the long term”
e1“cider apple ( Malus ×domestica Borkh.) cultivars”
Claim · model-written summary
A target density of nine fruit/cm 2 reduced biennial bearing without reducing juice quality.
- Taxon
- appleMalus domesticae1
- Treatment
- nine fruit/cm 2e0
- Outcome
- biennial bearinge0
- Direction
- decreasee0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a target crop density of nine fruit/cm 2 was found to adequately decrease biennial bearing while also not diminishing juice quality”
e1“cider apple ( Malus ×domestica Borkh.) cultivars”