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  • Author or Editor: L. J. Kushman x
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Abstract

On 15 occasions, either Wolcott, Jersey, Morrow or Murphy cultivars of highbush blueberry (Vaccinium corymbosum L.) were harvested by commercial hand-pickers and over-the-row mechanical harvesters in eastern NC during 1970 and 1971. Compared with hand-harvesting, machine-harvesting reduced yield of marketable ripe fruit 19 to 44%. Compared with commercially hand-harvested fruit, machine-harvested fruit was 10 to 30% softer in compression tests; and when held for 7 days at 21°C, the fruit developed 11 to 41% more decay. Machine-harvested fruits sorted on a commercial cleaner were softened still more and developed 5 to 10% more decay than fruit mechanically harvested but not sorted.

Fifty times as many canes were damaged by mechanical harvesting as by hand-harvesting.

Open Access

Abstract

The 3-monoarabinosides and 3-monogalactosides of delphinidin (Dp), petunidin (Pt), malvidin (Mv), and peonidin (Pn) as well as small amounts of the 3-monoglucosides of Dp, Pt, Mv, Pn, and cyanidin (Cy) were isolated from ripe blueberry fruit, variety ‘Croatan’. Small amounts of the 3-monogalactoside of Cy were present also. None of these 14 anthocyanins (Acy) were acylated. The major Acy were (in descending order): Mv-3-galactose, Dp-3-galactose, Dp-3-arabinose, Pt-3-galactose, Pt-3-arabinose and Mv-3-arabinose.

Open Access

Abstract

A method is described and test results reported for sorting blueberries with low-frequency vibration. Separation was dependent on fruit firmness which is affected by roughness of handling and other softening factors.

Firmness, as measured by compressing blueberries 0.2 cm between flat plates, statistically explained 58 to 72% of the variation in frequency for removal of berries from a vibrating trough with constant energy input. When comparing ripeness with frequency for sorting, light transmittance (∆OD; 740-800 nm) values, which indicate anthocyanin pigment concentration, explained only 10% of the variation in sorting frequency.

Berries of several cultivars and harvest dates were vibration sorted and tested for susceptibility to decay. Sorting frequency statistically explained 75% of the variation in decay level. Thus, the vibration method should be suitable for sorting blueberries into groups of different shelf life.

Open Access

Abstract

An Instron Universal Testing Machine was modified to measure firmness of blueberry fruit. Each blueberry was compressed between 2 flat surfaces for 1/4 its diameter at 1 cm/minute. Compression curves were linear. Small, green, unripe blueberries were extremely firm, softened appreciably as they ripened from the green to red stages but softened relatively little thereafter. Smaller blueberries tended to be slightly more firm than larger ones. Firmness varied from one harvest to another within a year and from one year to another. The firmness of fruit of some cultivars was almost double that of others. Firmness as measured by the Instron compared well (r = 0.70* and 0.81 *) with field (“chewing” or mastication) scores made by the breeder as part of his regular program. Blueberries dropped upon hard boards softened (bruised) in proportion to the distance of fall. Small increments (10.2 cm or 4-inch) of fall softened blueberries as much as large increments (40.6 cm or 16-inch) as long as the total distance (sum of increments) of fall was constant. Regardless of cultivar, size, ripeness, or initial firmness, the firmness of blueberries after a standard fall (8 drops of 40.6 cm or 16 inches each) can be predicted if their initial firmness (X) is known (Y = −0.590 + 0.627X). Bruised blueberries decayed more than those not bruised. Firmness of blueberries decreased when they were warmed and increased when they were cooled; this effect was a reversible, physical phenomenon.

Open Access

Abstract

Fruit of 104 clones and 75 seedlings of highbush blueberries were assayed for acidity, soluble solids, and keeping quality. From this group, 9 clones were selected to represent 4 extreme soluble solids and acid classes. These 9 clones were harvested over 2 years at 2 North Carolina locations. The previously reported relationships between high fruit acidity (Ac) or low soluble solids-to-acid ratio (SS/Ac) and high keeping quality (low DK) were extended from a few cultivars to a population of representative blueberry genotypes. Approximately 80% of the decay variability can be accounted for by various soluble solids and acid measures indicating that a soluble solids and acid measure would be useful to the breeder for segregating clones into those of poor, intermediate and good keeping quality. Suggested clonal discriminatory Ac, SS/Ac and pH x SS levels were proposed, and the possibility of field screening of blueberry clones for keeping quality potential was examined.

Open Access

Abstract

A pink (whitish)-fruited blueberry seedling that appeared in a hybrid highbush blueberry progeny in North Carolina is described. The major anthocyanins (Acy) detected in this seedling were arabinosides and galactosides of delphinidin, petunidin, and malvidin. The pink seedling had the same 15 possible combinations of 5 aglycones and 3 sugars previously reported for the normally blue-fruited cv. Croatan, but in smaller quantities. Total Acy contents of the pink seedling and 9 siblings ranged from 2.5 (pink fruit) to 49 (blue fruit) mg/10-g fruit. Acy content among the different clones was independent of berry pH, acidity (Ac), soluble solids (SS), or SS/Ac ratio. One hundred and seventy-five seedlings in this same progeny were scored for maximum berry color development. The results suggest that Acy expression is dependent on 1 or 2 major genes and that Acy content may be quantitatively inherited. For cultivars whose fruits are normally blue, the commercial use of blue fruit color as the major criterion of marketability (ripeness) may not be valid since color development is not necessarily related to berry ripeness and quality.

Open Access

Abstract

Vaccinium species collected from the eastern United States were grown and fruited at Castle Hayne, N.C. Harvest season extended from 5 June to 22 Aug. Vaccinium angustifolium Ait. was earliest ripening. Vaccinium myrtilloides Michx., V. elliotti Chap., diploid V. corymbosum L., and tetraploid V. pallidum Ait. populations also contained very early- to early-ripening seedlings. Early-ripening seedlings were not observed in tetraploid V. corymbosum populations and reached peak ripeness around mid-June, about with ‘Bluecrop’. One tetraploid V. corymbosum population continued ripening into early August. Vaccinium ashei Reade populations from Georgia began ripening about 2 weeks earlier than Florida V. ashei or Arkansas V. amoenum Ait. populations. One Georgia V. ashei population was only slightly later than tetraploid V. corymbosum. The Florida V. ashei populations continued ripening into late August. The diploid species V. darrowi Camp, V. tenellum Ait., and V. stamineum L., were all basically late in ripening. The potential utility of these species in breeding for both early- and late-ripening Vaccinium genotypes is discussed.

Open Access

Abstract

Eleven species in sections Cyanococcus and Polycodium of the genus Vaccinium were compared among themselves and with standard cultivars for soluble solids, titratable acidity, soluble solids/acid ratio, weight/berry (g), stem scar diameter (pedicel diameter at the berry), scar depth, fruit removal force (picking ease), and firmness. Vaccinium ashei Reade populations collected in either Florida or Georgia showed consistent differences in acidity, fruit size, and firmness. No such pattern in geographical differences occurred with V. corymbosum L. Vaccinium stamineum L. (section Polycodium) was outstanding for high soluble solids, large fruit size, small scar diameter, and firmness. Vaccinium elliottii Chapm. seemed promising for mechanical harvesting and processing with high-acid fruit, a favorable soluble solids/acid balance, small scar diameter, and easily harvested fruit. Vaccinium angustifolium Ait. was noted for high soluble solids, small shallow scar, and picking ease; V. pallidum Ait. for high soluble solids and small shallow scar; V. amoenum Ait. for small shallow scar and picking ease; and tetraploid V. corymbosum for high acidity and favorable soluble solids/acid balance. Sufficient variability occurred among and within species for selection for improvement of most traits; however, several generations of backcrossing or recurrent selection would be required for producing genotypes with commercial fruit size.

Open Access