This was our second week of maturity sampling. Apple fruit were again spot-picked on size and color from Adams County orchards. With the cooler than average temperatures and rainfall during the past week, both Gala cultivars responded with a nice increase in red color. Many of the red Gala fruit picked were 100% red, making it difficult to judge their ground color. While these Gala cultivars are getting redder, they are still quite firm and low in soluble solids.
Premier Honeycrisp and Honeycrisp fruit had much better size, but less red color than the Galas. The Premier Honeycrisp fruit are developing varietal flavor, softening and increasing in sweetness. The average firmness of Premier was unchanged from last week, but soluble solids (sweetness) increased from 11.0 °Brix to 13.7 °Brix.
Despite spot picking these samples, about half the Premier Honeycrisp fruit retained starch in the flesh while the other half of the fruit had lost much of their starch (See photo). Based on their starch pattern index, loss of firmness, ease of picking and the development of varietal flavor, Premier Honeycrisp harvest will begin shortly.
We have consistently seen a poor correlation between ground color and starch pattern index in both Premier Honeycrisp and Honeycrisp. This poor correlation certainly makes their harvest and storage much more difficult to manage.
With an early bloom, many people have been expecting an earlier harvest this year. The rapid maturation of Premier Honeycrisp underscores the need to be ready for an early apple harvest.
Here is a brief summary of our data from the second week's sampling:
|Cultivar||Diameter (inches)||Red Color (%)||Ground Color||Firmness (pounds)||Soluble Solids (°Brix)|
|Premier Honeycrisp||3.2||40||Greenish Yellow||16.5||13.7|
|Buckeye Gala||2.8||80||Greenish Yellow||21.7||11.1|
|Ultima Gala||2.8||70||Light Yellow||19.6||10.6|
Fruit color and starch staining pattern of representative samples of Premier Honeycrisp (top) and Honeycrisp (bottom) fruit harvested on August 9, 2017 in Adams County. This variable starch staining pattern in the Premier Honeycrisp apples was typical of the spot-picked fruit sampled. Photo: Kathy Hunt, University of Maryland
Fruit color and starch staining pattern of representative samples of Buckeye Gala (bottom) and Ultima Gala (top) apples harvested on August 9, 2017 in Adams County. The consistent loss of starch in the core region was similar in both red Gala cultivars. Photo: Kathy Hunt, University of Maryland