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University of Maryland Extension &
Department of Plant Science and Landscape Architecture, University of Maryland, College Park

Apple Maturity Assessments 2021: Premiere Honeycrisp and Honeycrisp Week 2

This is our second week of evaluating fruit for the 2021 apple maturity assessments. We assessed Premiere Honeycrisp on G11 and Firestorm Honeycrisp grafted on B9 (without any plant regulator application) located in the same farm in Smithsburg, MD. In general, Premiere Honeycrisp fruits are ready for spot picking this week, while Firestorm Honeycrisp is far behind yet. As expected, Premiere Honeycrisp advanced it maturity since last week, displaying average starch index values of 2.5, firmness values in the range of 15lbs, DA index values of 0.9, skin red coloration ~40% and soluble solids contents ~12-13%. The information for both cultivars is summarized in Table 1.
 

Color

Surface color (eye-balling): Premiere Honeycrisp fruits are showing an overall average 40% of red skin coloration, ranging from 20 to 60% coloration, while Honeycrisp fruits displayed values around 5%. 
Background color (DA index): Values are around 0.9 for Premiere Honeycrisp, while Firestorm Honeycrisp is >1 still. Readings of 0.60-0.70 are recommended for harvesting fruits for long-term storage, and we observed Premiere Honeycrisp fruit that already was in this range, thus ready for spot picking. An index of about 0.35 is targeted for harvesting fruit for short-term storage (which we have not observed yet). 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: There were significant differences in firmness between both assessed cultivars. Premiere Honeycrisp fruit are displaying firmness values around 15lbs (ranging from 13-17lbs), while Honeycrisp fruit are showing an average of 21-22 lbs. In general, apples that are destined for long-term storage (>3 months) should be harvested with a firmness of at least 15lbs; while for fruit for shorter-term storage (1-2 months) a firmness of 13-15 lbs is appropriate. For Premiere Honeycrisp we already assessed fruit that is displaying firmness for long-and short-term storage. Firmness was measured with a penetrometer with a 7/16-inch diameter plunger.
 

Starch

Starch content: Firestorm Honeycrisp fruit is at the lower end of the scale (1.0) still, while Premiere Honeycrisp fruits are showing a higher degree of starch disappearance in the flesh around 2.5. It is important to mention that we did observe Premiere Honeycrisp fruit with values around 4-5, ready for spot picking, while others still on the 1.5 range. 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 increased their values and are averaging 12-13%, while Honeycrisp is around 11%. In general, it is recommended to harvest fruits with readings around 12% to 14% SSC, another reason why spot spiking Premiere Honeycrisp this week is recommended.

Acidity: Our results show that Premiere Honeycrisp decreased it acidity values since last week to ~0.8%, while Firestorm Honeycrisp fruit was ~1%. 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 Premiere Honeycrisp and Honeycrisp harvested from Smithsburg, Maryland. Values in parentheses indicate the results from last week’s monitoring.
Cultivar Premiere Honeycrisp Firestorm Honeycrisp
Date 29-Jul 29-Jul
Rootstock G11 B9
Diameter (in) 3.5 (3.3) 3.3
Skin Red Color (% blush) 40 (20) 5
DA Index 0.9 (1.4) 1.7
Firmness (lbs) 15 (15.4) 21.6
Starch Index (Cornell 1-8) 2.5 (1.5) 1.0
Soluble Solids (%) 12.7 (11.3) 10.9
Acidity (% Malic Acid) 0.8 (1.0) 1.0
Fruit View

Premiere Honeycrisp 



Firestorm Honeycrisp

Meet the Team
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.
 
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. 
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
 
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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University of Maryland Extension - Fruit Maturity News · 28647 Old Quantico Rd · Wicomico County Extension Office · Salisbury, MD 21801-8045 · USA

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