Cucurbit Genetics Cooperative Report 3:15-16 (article 9) 1980
The Effect of Fruit Size on Various Fruit Quality Characteristics
J. Mather and R. L. Lower
University of Wisconsin,
Madison, WI 53706
Fruit firmness is an important factor in assessing the
quality of pickling cucumbers. The most frequent measurement
of fruit firmness is pounds of pressure as determined by
a Magness Taylor Fruit firmness is pounds of pressure as
determined by a Magness Taylor Fruit Pressure Tester (MTFPT)
equipped with a 7.9 mm tip plunger. A study was made to
determine the relationship of fruit diameter, the fruit
skin, and tip placement on MTFPT readings taken on fresh
fruit. Assessments of placental hollowness and carpel separation
were made on larger fruit.
Plants of the cv. 'Calico' were grown at the Hancock, WI
Experimental Station using standard cultural practices.
Five sections of 30ft of row were used as replications.
The fruit were harvested in mid-september and graded by
hand. Fruit grading was based on PCIC standards (Table
1). A 20 fruit sample of each size from each replication
was selected bases on uniform shape. The skin was removed
about 25.4 mm from both the stem and blossom end from one-half
of the sample (ten fruit). Pressure tests were taken at
both ends of fruit with and without skin. The plunger was
placed at the juncture of two carpels, one-third of the
distance from either the stem or blossom end, and penetration
was at a 90° angle to the plane of the fruit which was
on a solid platform. Only one measurement was obtained at
each end. Fruit of the two largest sizes were cross-sectioned
at both ends and the middle, and were checked for placental
hollowness and carpel separation. The diameter of the fruit
and the seed cavity were measured from the middle cross-section.
Pressure tests were significantly greater with the skin
on the fruit and generally increased with increased diameter
at both stem and blossom ends (Table 1). Pressure tests
on fruit without skin were greater in size 2 than size 4
at the stem end. A similar pattern was observed at the blossom
end where size 2 fruit had higher readings than both sizes
3 and 4. Measurements were greater at the stem end than
at the blossom end and the relationship is fairly constant.
Tests at the stem end are about 1.25 lbs higher than the
blossom end. Thus, it seems that only one reading per fruit
is necessary to test relative firmness as long as it is
taken at the same end of all fruit.
the incidence of placental hollowness and carpel separation
was almost exclusively confined to the largest sized fruit
(Table 2). The relationship between diameter of the seed
cavity and fruit diameter was expressed as interior ratio
and was not significantly different in sizes 3 and 4, thus
as the fruit increased in size, the relative size of the
seed cavity remained constant. Further investigation will
be necessary to test the relationship of these fresh fruit
data and brinestock quality.
Table 1. Effect of fruit size, skin, and plunger placement on fruit firmness readings.
z Size based on PCIC standards |
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y Pounds of pressure determined by using Magness Taylor Fruit Pressure Tester with 7.9 mm tip.
Table 2. Effect of fruit size on several fruit quality factors.
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Seed cavity diameter (mm)y
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z Size based on PCIC standards. Size 3 = 3.8 cm to 5.1 cm diameter; size 4 = over 5.1 in diameter.
y Mean of 50 fruit.
x Based on seed cavity diameter/fruit diameter.
