Final Apple Maturity Assessment of 2021: Cripps Pink and Evercrisp Week 14
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On our fourteenth and final week of apple fruit maturity assessment report, we continued to evaluate Evercrisp on G11 from Smithsburg, MD and Cripps Pink fruit from this same location. None of these fruit have received any plant growth regulator. Evercrisp fruit are ready to be harvested as they are displaying >70% of red coloration, maintained firmness values ~19lbs, increased their flesh starch disappearance values to 6.5 as well as their soluble solids contents to 17.4%. We have seen an increase in the presence of the physiological disorder of watercore in Evercrisp apples, which is known to increase with maturity. Cripps Pink apples, advanced in their maturity, but, as expected, are still not ready to harvest until November, displaying high flesh firmness values (~19.5 lbs) and starch disappearance values of ~2.1. The information is summarized in Table 1. We acknowledge the important contributions of collaborators following the table.
Color
Surface color (eye-balling): Evercrisp fruit are presenting > 70% of skin red color, as reported last week, while Cripps Pink increased its red coloration from ~35% to ~42% this week.
Background color (DA index): Evercrisp maintained its values in ~0.7 this week, while Cripps Pink fruit are decreased their values to 1.2 with respect to the 1.3 that we had reported last week. Fruit were measured with a DA meter, a device that measures the absorbance difference between 670 nm and 720 nm light. A higher DA index indicates a larger content of chlorophyll-a in the fruit skin.
Firmness
Fruit firmness:This week of evaluation, Red Delicious fruit have maintained their firmness in ~16lbs, which is characteristic of this cultivar and falls into the recommended firmness harvest window for long-term storage. Aztec Fuji decreased its flesh firmness in almost a pound to values ~17 lbs. Firmness was measured with a penetrometer with a 7/16-inch diameter plunger.
Starch
Starch content: Evercrisp and Cripps Pink increased its starch disappearance from what we measured last week and are now displaying values of ~6.5 and ~2.1, respectively. The common starch index rating system (Cornell chart) on a scale from 1 to 8, where 1 is full starch (all blue-black) and 8 is starch-free (no stain), was used. In general, on a 1 to 8 scale, values ranging from 5-6 are recommended for harvesting Evercrisp apples for storage.
Sugars and Acids
Soluble solids contents (SSC): SSC values, measured with a portable refractometer, are showing an increase in values for Evercrisp from ~17 to ~17.4%, characteristic of this cultivar. It is worth indicating that we observed the presence of watercore to continue to develop in this cultivar, which will increase as the fruit is left longer on the tree. In general, it is recommended to harvest Evercrisp fruit with readings > 14% SSC. Cripps Pink increased their values to 12.3%, over the minimum 12%.
Acidity: Evercrisp and Cripps Pink fruit decreased their acidity values to ~0.52 and ~0.54, respectively. A decrease in acidity content is an indicator of advancing maturity, reason why this indicator is included in this report. Acidity was measured with an automatic titrator, quantifying malic acid (the major acid present in the juice of apples).
Table 1. Summary table of maturity assessments for Cripps Pink and Evercrisp harvested from Smithsburg, Maryland. Values in parentheses indicate the results from last week’s monitoring.
| Location |
Smithsburg, MD |
Smithsburg, MD |
| Cultivar |
Cripps Pink |
Evercrisp |
| Date |
21 Oct |
21 Oct |
| Rootstock |
G11 |
G11 |
| Diameter (in) |
3.1 (3.1) |
3.6 (3.6) |
| Skin Red Color (% blush) |
42 (35) |
74 (72) |
| DA Index |
1.2 (1.3) |
0.7 (0.8) |
| Firmness (lbs) |
19.5 (20) |
19 (19.5) |
| Starch Index (Cornell 1-8) |
2.1 (1.75) |
6.5 (5.5) |
| Soluble Solids (%) |
12.3 (11.9) |
17.4 (17) |
| Acidity (% Malic Acid) |
0.54 (0.6) |
0.52 (0.59) |
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This project was funded by Maryland State Horticultural Society (MSHS) and from start-up funds of Dr. Macarena Farcuh. Special thanks to Matt Harsh (78 Acres, LLC), Brian Jacques (Edgemont Orchards), Steve Blades (Blades Orchards) as well as to Joy Cline (Bear Mountain Orchards) that allowed us to harvest fruit for analysis. Thanks to Dr. Haley Sater, Agriculture Extension Agent of Wicomico County for University of Maryland Extension for sample collection support and of course to her valuable collaboration. Thanks to all the students in the Farcuh Lab in the Department of Plant Sciences and Landscape Architecture at the University of Maryland for assistance in conducting all the maturity analyses. Thank you all for subscribing!
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Smithsburg, MD
Cripps Pink
Smithsburg, MD
Evercrisp
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Macarena Farcuh is an Assistant Professor of Horticulture in the Department of Plant Science and Landscape Architecture. She is interested in investigating how to develop novel strategies for improving fruit quality, nutritional value, shelf-life capacity, safety and marketability throughout fruit development, harvest and postharvest storage. Macarena’s research program integrates diverse approaches, including systems biology, physiology, biochemistry, analytical chemistry, molecular biology, and sensory science. Her goal is to contribute to decrease fruit loss/waste, support environmental sustainability and, at the same time, enhance fruit consumption by meeting consumers’ expectations and thus improve the health and well-being of populations.
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Haley Sater is an agricultural extension agent for Wicomico County specializing in fruit and vegetable production. She is interested in connecting with produce growers across Maryland to identify and promote profitable and sustainable fruit and vegetable systems. Her background is in small fruits and plant breeding.
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Contact Us: Macarena Farcuh, Ph.D.
Assistant Professor and Extension Specialist
University of Maryland, College Park
Email: mfarcuh@umd.edu
or
Haley Sater Ph.D.
Wicomico County Extension Educator
Wicomico County Extension Office
28647 Old Quantico Rd, Salisbury
Email: hsater@umd.edu
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The University of Maryland, College of Agriculture and Natural Resources programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, or national origin, marital status, genetic information, or political affiliation, or gender identity and expression.
Los programas del Colegio de Agricultura y Recursos Naturales de la Universidad de Maryland están abiertos a todos y no discriminará contra nadie debido a raza, edad, sexo, color, orientación sexual, discapacidad física o mental, religión, descendencia, origen nacional, estatus matrimonial, información genética, afiliación política, o identificación y expresión de género.
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