( Steckel et al., 1989 ; Ward et al., 1992 ). Chlorophyll in white-seeded Phaseolus vulgaris seeds is visible and may be detected and sorted by color-sorting seed conditioning equipment ( Lee et al., 1998 ). Another non-destructive technique for assessing
Abstract
Green fruits of tomato (Lycopersicon esculentum Mill.) of 4 different cultivars, including 2 having the crimson fruit character (ogc ), were sorted photometrically into 2 sub-samples of comparable maturity. One subsample was treated with ethylene gas and the ripening behavior of both was followed. The photometric sorting technique was superior to visual classification in providing uniform fruit maturity classes of the crimson-type fruit. These fruit responded normally to ethylene ripening when compared to standard cultivars.
Abstract
Researchers working with strawberries often find it necessary to size, grade, count, and weigh the fruit (1, 2, 3, 4). These tasks present problems when the research involves a large number of test plots. Size-yield classifications of hand-sorted fruit are not only time-consuming, but are subject to human error. A strawberry sorter for research use was developed to reduce these problems.
Chloroplast fluorescence as a nondestructive tool for assessing `Red Delicious', `Golden Delicious' and `Law Rome' apple fruit quality was examined after approximately 4.5 months storage. Fluorometry parameters of minimal fluorescence (Fo), maximal fluorescence (Fm) and quantum yield (Fm-Fo)/Fm (otherwise denoted as Fv/Fm) were determined. All fluorescence parameters declined with time as apple fruit were maintained at 22°C in air. Fv/Fm was found to correlate well with firmness for `Red Delicious' fruit. A decline in Fo with time correlated very well with the development of yellow coloration of `Golden Delicious' fruit. The Fv/Fm value was consistently higher for controlled-atmosphere (CA) stored fruit than for regular-air (RA) stored fruit. When CA and RA stored `Law Rome' fruit were combined and a Fv/Fm value of 0.685 was used to resegregate fruit from the two storage regimes. Resegregation was achieved with 75% accuracy, with only 5% RA-stored fruit incorrectly identified as CA-stored. The accuracy, speed of assessment and light-based nature of fluorometry suggest it may have some practical use as a tool for sorting apple and other chlorophyll-containing fruit on commercial packinglines.
We have developed an electronic sensor (“sniffer”) that measures fruit ripeness rapidly and nondestructively by measuring the aromatic volatiles that are naturally emitted by ripening fruit. In this study, we evaluated the potential of using the fruit ripeness sniffer in the quality sorting of blueberries. Blueberries were first visually classified into four distinct ripeness classes: unripe; half-ripe; ripe; and over-ripe and quantitatively measured for color, firmness, TSS, and sugar acid ratio. Ripeness classification accuracy with the sniffer matched or exceeded that of all other ripeness indices. The sniffer differentiated unripe, ripe and over-ripe berries within one second, but could not distinguish between the unripe and half-ripe class. Detection of l-2 damaged or 1-2 soft fruit spiked within a large container of 24-37 high quality ripe fruit was also achieved, but required a response time of 10 seconds. Electronic sensing of aromatic volatiles may be a useful new technique in the grading and sorting of blueberries.
Abstract
The current axiom is that passage of plant cells through tissue culture results in increased genetic variability. The major task confronting anyone who would harness this new genetic variability is to recover the rare, desirable genotypes from the large number of other genotypes. This task is accomplished easily if the desired phenotype is controlled by a single gene, and expressed at the cellular level in vitro. Tolerance of plants to stresses often do not exhibit these characteristics. We will consider several approaches to developing novel selection systems for complex, agricultural traits.
Trends in chlorophyll fluorescence for `Starking Delicious', `Golden Delicious' and `Law Rome' apple (Malus ×domestica Borkh.) fruit were examined during the harvest season, during refrigerated-air (RA) storage at 0 °C, following RA and controlled-atmosphere (CA) storage, and during a poststorage holding period at 22 °C. Fluorescence parameters of minimal fluorescence (Fo), maximal fluorescence (Fm), and quantum yield [(Fm-Fo)/Fm, otherwise denoted as Fv/Fm] were measured. During `Starking Delicious' fruit maturation and ripening, Fv/Fm declined with time, with the rate of decline increasing after the ethylene climacteric. During RA storage, all fluorescence parameters remained constant for approximately 2 weeks, then steadily declined with time for `Starking Delicious' fruit. Superficial scald was detected after Fv/Fm had declined from an initial value of 0.78 to ≈0.7. Fv/Fm was consistently higher for CA-stored fruits than for RA-stored fruits. We were able to resegregate combined populations of “high-quality” (CA) and “low-quality” (RA) `Law Rome' fruit with 75% accuracy using a threshold Fv/Fm value of 0.685, with only 5% RA-stored fruit incorrectly identified as being of high quality. During a poststorage holding period, Fo, Fm, and Fv/Fm correlated well with firmness for `Starking Delicious', but not for `Golden Delicious' fruit, which were already soft. Fo and Fm were linearly correlated with hue angle for 'Golden Delicious' fruit, decreasing as yellowness increased. The accuracy, speed of assessment, and light-based nature of fluorescence suggests that it may have some practical use as a criterion to assist in sorting apple or other chlorophyll-containing fruit or vegetables on commercial packing lines.
Tulip bulbs are produced in the Netherlands and are shipped to United States during the months of July and August in temperature-controlled shipping containers. Each shipment is often composed of a mixture of many cultivars. Mechanical failure of temperature controls may result in high temperatures that ultimately may reduce forcing quality of the bulbs. When such accidents occur, an immediate decision must be made about whether to invest more time and money on these potentially damaged bulbs. Such a decision is not easy because symptoms of heat damage are often delayed until months later. Research on a single cultivar, `Apeldoorn', has shown that heat stress can cause flower abortion and other abnormalities. However, cultivars undoubtedly vary in their response to heat stress. Thus in the 2002 and 2004 forcing seasons, ≈45 cultivars were screened for response to a standard heat stress of 4 days at 35 °C. Prior to the heat stress, bulbs were held at 17 °C or 9 °C for 4 weeks, mimicking conditions used for late and early forced bulbs, respectively. Flower and leaf height, percent flower abortion, and flowering date were evaluated. Heat stress caused flower abortion and reduced plant height in sensitive cultivars. Across all cultivars, cold storage prior to the heat stress significantly increased bulb's sensitivity to heat stress. Using percent flower abortion, cultivars were grouped into three categories: resistant, moderate, and susceptible. With this information, we hope that damage assessment may become easier and fewer bulbs wasted.
were cracked with a mechanized cracker ( Lane, 2000 ) and kernel and shell weights were obtained. The largest piece of each nut was visually sorted into light, medium, and dark categories for each cultivar. Kernel color (L*, C, and H) of this piece was
Mechanized harvest for processing markets has become commercially accepted for blackberries (Rubus sp.), highbush (Vaccinium corymbosum), lowbush (V. angustifolium) and rabbiteye (V. ashei), blueberries, cranberries (V. macrocarpon), grapes (Vitus labruscana, V. vinifera, V. rotundifolia, V. sp.), raspberries (Rubus ideaus) and to a lesser extent for strawberries (Fragaria × ananassa). Fruit bruising during harvest and sorting often contributes to reduced “eye appeal” and keeping quality for fresh sales. Highbush and rabbiteye blueberries are successfully machine harvested for fresh markets, however, high temperature and rain will often make product quality unacceptable. Highbush blueberries grown in cool climates and rabbiteye blueberries with greater inherent resistance to bruising have most consistently given acceptable quality. Cultivar improvement and equipment that causes less bruising during harvest and sorting will be required for increased mechanization for fresh markets. Mechanical pruning of blackberries, blueberries, grapes and raspberries can reduce costs by up to 80%. The audience will be involved in discussion of advancements in mechanization techniques.