Apple Maturity Assessments 2020: Week 6 BC2 Fuji

Although the anticipated harvest is scheduled for the end of the month, we observed high soluble solids contents (>14 %) accompanied by a high percentage of red skin coloration (influenced by the lower temperatures that we have been experiencing). Fruits are still firm (~18 lbs, possibly influenced by the ReTain application), displaying high DA index values (~1.1) and a starch pattern index of 3.8.

The information is summarized in Table 1.

BC2 Fuji Results

Color

Surface color: BC2 Fuji fruits presented an average of 70% of red skin coloration. The high blush percentage can be influenced by the cooler temperatures we have been experiencing during the past weeks.

Background color (DA index): DA index values ranged between 1.0 and 1.1, while readings <0.8 are recommended for harvesting fruits for long-term storage.

Fruit firmness

Fruits are displaying high firmness values (~18 lbs), which can be related to the ReTain application that they received. Firmness was measured with a penetrometer with a 7/16-inch diameter plunger.

Starch content

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 to evaluate the fruits. BC2 Fuji fruits this week displayed a starch index value of 3.8. 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.

Soluble solids contents (SSC)

SSC values are around 14-15%, contributing to the popularity of BC2 Fuji as a sweet apple, as we are still a few weeks ahead of its anticipated harvest.

Acidity

Malic acid values were measured at 0.5% on average for all the evaluated fruits, and we expect this value to decrease, as a decrease in acidity contents is an indicator of advancing maturity.

Table 1. Summary table of maturity assessments for BC2 Fuji. For fruit labeled with *, a ReTain application at the full rate was done on 10/1.