Agriculture Reference
In-Depth Information
Table 10.7
Minimum Flesh Firmness (Measured at the Weakest Point on the
Fruit) Necessary to Avoid Commercial Bruising at Three Levels of Physical
Handling.
Drop Height
z
(1 cm)
∼
66 G
(5 cm)
∼
185 G
(10 cm)
∼
246 G
Weakest
position
Cultivar*
Plums
Blackamber
0
0
3
z
Tip
Fortune
0
0
0
Shoulder
Royal Diamond
0
0
0
Shoulder
Angeleno
0
0
0
Shoulder
Peaches (yellow flesh)
Queencrest
0
4
9
Tip
Rich May
0
0
9
Tip
Kern Sun
2
6
9
Tip
Flavorcrest
3
5
6-9
Tip
Rich Lady
6
10
11
Shoulder
Fancy Lady
3
7
11
Shoulder
Diamond Princess
0
0
9
Shoulder
Elegant Lady
3
5
6-9
Shoulder
Summer Lady
0
0
8
Shoulder
O'Henry
3
5
6-9
Shoulder
August Sun
3
4
9
Shoulder
Ryan Sun
0
0
10
Shoulder
September Sun
0
4
9
Shoulder
Nectarines (yellow flesh)
Mayglo
4
8
11
Tip
Rose Diamond
6
7
8
Suture/Shoulder
Royal Glo
0
9
11
Shoulder/Tip
Spring Bright
6
10
10
Shoulder
Red Diamond
6
7
11
Shoulder
Ruby Diamond
4
9
9
Shoulder
Summer Grand
2
5
6
Shoulder
Flavortop
3
6
6
Tip
Summer Bright
0
6
8
Shoulder
Summer Fire
0
0
9
Shoulder
August Red
2
12
12
Shoulder
September Red
0
0
10
Shoulder
Note: Fruit firmness measured with an 8 mm tip and express as Kg-force.
a
PVC belt. Damaged areas with a diameter equal to or greater than 2.5 mm
were measured as bruises.
Dropped on 1/8
″
fruit in the palm of the hand ('spring'), is also a useful matu-
rity index for a few cultivars, especially those that achieve
full colour several weeks prior to harvest. A two-tier maturity
system is currently used in California: U.S. Mature (mini-
mum maturity), and California Well-Mature. Measurement of
fruit firmness is recommended for plum cultivars where skin
ground colour is masked by full red or dark colour develop-
ment before maturation. Flesh firmness, measured using a
penetrometer (8 mm tip), can be used to determine a maxi-
mum maturity index, which is the stage at which fruit can
