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Kathleen B. Evensen, Joseph M. Russo, and Harriet Braun

Grading criteria are proposed for judging potatoes (Solanum tuberosum) for chip quality and yield. The criteria were derived from a decision-making scheme developed from expert opinions, U.S. Dept. of Agriculture grades, and a statistical evaluation of stored potatoes. The criteria are presented as ranges of acceptable values for a limited set of variables found to be important for chip quality and yield. These variables include bruising, cracks, cuts, fusarium dry rot, lesions, and scab. The proposed criteria, besides being a practical decision-making tool for processors, could serve as a knowledge base for potato expert systems and the development of mechanized sorting equipment.

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J.W. Scott, S.M. Olson, H.H. Bryan, J.A. Bartz, D.N. Maynard, and P.J. Stoffella

`Solar Fire' is a heat-tolerant hybrid tomato (Solanum lycopersicum L. formerly Lycopersicon esculentum Mill.) with resistance to all three races of Fusarium wilt incited by Fusarium oxysporum f. sp. lycopersici Sacc. Snyder & Hansen. It has superior fruit-setting ability in comparison with most existing cultivars under high temperatures (>32 °C day/>21 °C night), and the fruit crack less under the rainy field conditions often present in the early fall Florida production season. Fla. 7776 is the pollen parent in `Solar Fire', providing much of the heat tolerance in this hybrid. It has large fruit-providing breeders with a parent to produce heat-tolerant hybrids with two heat-tolerant parents.

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Tanachai Pankasemsuk, James O. Garner Jr., Frank B. Matta, and Juan L. Silva

Characteristics of mangosteen fruit with normal and translucent flesh were determined. Fruit exhibiting translucent flesh disorder had significantly higher rind (65%) and flesh (82%) water content than fruit with normal flesh (63% and 80% in the rind and flesh, respectively). Specific gravity of translucent flesh fruit was >1 and that of normal flesh fruit was <1. Fruit specific gravity and natural transverse rind cracking were used to separate translucent-fleshed fruit from normal fruit. Translucent-fleshed fruit had a lower soluble solids concentration and titratable acid percentage than normal fruit. Translucent flesh was induced in normal fruit following water infiltration at 39 kPa for 5 minutes.

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E. Cohen, B. Shapiro, Y. Shalom, and J.D. Klein

Water loss was found to be a nondestructive indicator before visible symptoms of chilling injury (CI) in cold-stored grapefruit (Citrus paradisi Macf.) and lemon (C. limon L. Burm. f.). The water-loss rate increased significantly after removing the fruit from cold storage and holding at 20C. Scanning electron microscopy revealed large cracks around the stomata. Changes in electrical conductivity of the flavedo tissues, total electrolyte leakage, and K+ or Ca2+ leakage were all inadequate predictors of CI, appearing only after CI was evident.

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Ross E. Byers

AVG applied 2 to 6 weeks before the optimum harvest date for several cultivars dramatically reduced pre-harvest fruit drop. The loss of fruit firmness and starch loss after the optimum harvest date was reduced by AVG sprays. The development of watercore in `Starkrimson Delicious' and `York' and maturity cracking in `Rome' and `Golden Delicious' were delayed and/or prevented by AVG. Color development was slightly delayed for most red cultivars and `Golden Delicious'. Soluble solids concentration was generally unchanged. Airblast applications of 123 g·ha–1 AVG was no more effective than a standard rate of NAA (28 to 56 g·ha–1), but rates of 248 g·ha–1 AVG and above were more effective than NAA for most cultivars. When fruit were left on the tree for periods of 3 to 5 weeks after the optimum harvest date, NAA hastened the loss of fruit firmness and starch and NAA increased watercore of `Delicious' and maturity cracking of `Golden Delicious' and `Law Rome'. Soluble solids and red color were generally unaffected by NAA. Ethephon sprays hastened the rate of fruit drop. When NAA was tank mixed with ethephon, NAA delayed fruit drop caused by ethephon, but AVG did not. The use of superior oil or Regulaid surfactant did not affect NAA or AVG responses; however, the silicone surfactant Silwet L-77, in one experiment, promoted the effectiveness of AVG. Tank mixing NAA or AVG with pesticides (Guthion + Lannate + Captan) did not affect the responses of AVG or NAA on fruit drop.

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Amy Oberly, John Masiunas, and Mosbah Kushad

Rye (Secale cereale) residues used in an alternative cropping system will affect nutrients, soil moisture, and soil temperatures. Each of these factors can affect tomato fruit quality. A field study was conducted comparing the effects of a rye cover crop, tomato variety, and N fertility on tomato fruit quality. In October, cereal rye was seeded at 100 kg·ha–1 to one-half of the plots. The rye was killed in mid-May by applying glyphosate at 1.1 kg·ha–1. Tomato seedlings were planted into the rye and bare-ground plots in late May. Four tomato varieties differing in cracking and soluble solids were used. There were two fertilizer regimes, no additional fertilizer, and N fertilizer applied broadcast before tomato planting, and as a sidedress based on soil tests, leaf analysis, and current recommendations. Tomato quality was evaluated based on 1) color as assessed using a Minolta chromameter, 2) cracking based on type and severity, and 3) soluble solids as determined by HPLC.

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W.J. Sperry, J.M. Davis, D.C. Sanders, and P.V. Nelson

Fresh-market tomato (Lycopersicon esculentum Mill.) was grown in a growth chamber, hydroponically, and in a field to evaluate the effect of foliar-applied boron (B) and root-applied K on growth, yield, quality, and tissue nutrient levels. Plant and root dry weight, plant height, fruit set, total yields, marketable yields, fruit shelf life, fruit firmness, and fruit crack were positively influenced by B treatments. Boron-treated plants contained more K than plants not treated with B. Plants not treated with B contained less calcium (Ca) than plants treated with B. Leaflets from plants treated with B maintained higher K levels during fruit development than leaflets from plants not treated with B. Roots from plants treated with foliar B had significantly more B than roots from plants not treated with B. Fruit from B-treated plants had significantly more B than fruit from plants not treated with B. This indicates B was translocated from leaves to root and fruit tissues.

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Fahad Al-Said and Donald J. Huber

A general feature of tomato fruit containing genetically reduced levels of polygalacmronase activity is decreased deterioration and cracking, particularly when handled at the ripe and over ripe stages. As fully ripe fruit are metabolically compromised and very prone to mechanical injuries, we investigated the influence of impact bruising on electrolyte leakage, pectin solubility, and depolymerization in ripening tomato fruit.

`Sunny' tomato fruit harvested at the mature-green, turning, and ripe stages of development and subjected to controlled impact injury exhibited elevated ethylene production at all developmental stages. Subsequent analyses were performed on discs prepared from bruised and uninjured pericarp tissue. Discs from bruised tissues exhibited enhanced electrolyte leakage and, in bruised tissues from ripe fruit, enhanced pectin efflux. Levels of soluble pectins derived from ethanol-insoluble powders were unaffected by bruising; however, pectins from bruised ripe fruit exhibited mol wt downshifts relative to those from nonbruised tissues.

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M.E. Ostry and P.M. Pijut

Butternut (Juglans cinerea L.) has many fine qualities as a nut species, however, it has never been commercially important. Although the nut is very edible, only a few cultivars have been selected that have desirable nut size and cracking qualities. In the last 20 years there has been a dramatic decline in the number of butternut in native stands caused to a large extent by the lack of natural reproduction and a damaging canker disease. Evidence suggests that superior, disease resistant trees can be propagated and if isolated from areas where the disease is prevalent, may remain disease-free. It is important that the remaining genetic diversity within the species is maintained. Various butternut conservation practices and research projects to restore butternut populations are underway in the United States and Canada.

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J.L. Smilanick, F. Mlikota, P.L. Hartsell, J.S. Muhareb, and N. Denis-Arrue

`Ruby Seedless', `Red Globe', and `Prima Red' table grapes were fumigated with the treatment schedule of the USDA-Animal Plant Health Inspection Service recommended for the control of mealybugs. Methyl bromide was applied at 64 g·m-3 (4.0 lb/1000 ft3) for 2 h at 16.1 to 18.3 °C (61 to 65 °F). The grapes were in commercial packages typical for each cultivar. After fumigation and 30 min of aeration, the grapes were stored 2 to 4 weeks at 5 °C (41 °F) and their quality assessed by evaluation of cluster rachis condition, shatter, berry cracking, decay, berry color, internal browning, bleaching injury, and firmness. None of the table grape quality parameters was significantly influenced by methyl bromide fumigation.