Apple Maturity Assessments 2022: Premiere Honeycrisp and Honeycrisp Week 3
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We are now entering our third week of evaluating fruit apple maturity. We continued assessing Premiere Honeycrisp on G11 and Firestorm Honeycrisp grafted on B9 (without any plant regulator application) located in the same farm in Smithsburg, MD. This is the last week of evaluating Premiere Honeycrisp, as fruits from this cultivar are ready for harvest, displaying flesh starch disappearance values of 6.5, firmness values ~13.5 lbs, DA index values of 0.3, skin red coloration >50% and soluble solids contents ~13.5%. Regarding Honeycrisp fruits, as compared to last week, they are advancing in maturity but still not ready for harvest for long-term storage. The information is summarized in Table 1.
Color
Surface color (eye-balling): Premiere Honeycrisp fruits are showing an overall average 50 to 60% of red skin coloration, indicative of a highly marketable fruit, while Honeycrisp fruits displayed values around 10%.
Background color (DA index): Values are around 0.3 for Premiere Honeycrisp, while Firestorm Honeycrisp is >1 still. Readings of 0.6-0.7 are recommended for harvesting fruits for long-term storage, and we observed Premiere Honeycrisp fruit that already was in this range, thus ready for harvest for this purpose. An index of about 0.35 is targeted for harvesting fruit for short-term storage. Fruits 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: Firestorm Honeycrisp fruit is at the lower end of the scale (1.5), while Premiere Honeycrisp fruits are showing a flesh starch disappearance value of 6.5. Premiere Honeycrisp fruit displayed an important increase in starch disappearance as compared with last week, and is ready for harvesting for fresh market. 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 4-6 are recommended for harvesting apples for long-term storage, while 6-7 for fresh market.
Starch
Starch content: Firestorm Honeycrisp fruit is at the lower end of the scale (1.5), while Premiere Honeycrisp fruits are showing a flesh starch disappearance value of 6.5. Premiere Honeycrisp fruit displayed an important increase in starch disappearance as compared with last week, and is ready for harvesting for fresh market. 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 4-6 are recommended for harvesting apples for long-term storage, while 6-7 for fresh market.
Sugars and Acids
Soluble solids contents (SSC): SSC values, measured with a portable refractometer, are showing that Premiere Honeycrisp fruit are averaging 13.5%, while Honeycrisp is around 12%. In general, it is recommended to harvest fruits with readings around 12% to 14% SSC, range already reached by Premiere Honeycrisp fruit.
Acidity: Our results show that Premiere Honeycrisp decreased it acidity values since last week to ~0.6%, while Firestorm Honeycrisp fruit was still constant in ~0.7%. A decrease in acidity content is an indicator of advancing maturity, which is the 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 Premiere Honeycrisp and Honeycrisp harvested from Smithsburg, Maryland. Values in parentheses indicate the results from last week’s monitoring.
| Location |
Smithsburg, MD |
Smithsburg, MD |
| Cultivar |
Premiere Honeycrisp |
Firestorm Honeycrisp |
| Date |
8 Aug |
8 Aug |
| Rootstock |
G11 |
B9 |
| Diameter (in) |
3.2 (3.1) |
3.3 (3.2) |
| Skin Red Color (% blush) |
51 (40) |
12 (8) |
| DA Index |
0.3 (0.8) |
1.3 (1.5) |
| Firmness (lbs) |
13.5 (15.0) |
19.0 (20.8) |
| Starch Index (Cornell 1-8) |
6.5 (3.0) |
1.5 (1.0) |
| Soluble Solids (%) |
13.5 (12.5) |
12 (11.5) |
| Acidity (% Malic Acid) |
0.6 (0.7) |
0.7 (0.7) |
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Smithsburg, MD
Firestorm Honeycrisp
Smithsburg, MD
Premiere Honeycrisp
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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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