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  • Author or Editor: S. B. Kelly x
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Fusarium root rot is a major limiting factor in snap bean (Phaseolus vulgaris L.) production. The level of genetic resistance in commercial bean cultivars is minimal and disease is frequently exacerbated by environmental factors. We investigated the contribution of vigorous, adventitious roots to enhancing root rot tolerance in snap bean. Seedling root system architecture was evaluated in 17 recombinant inbred lines (RILs) from a cross of a resistant snap bean line (FR266) and a susceptible dry bean cultivar (Montcalm). The RILs varied in tolerance to Fusarium root rot. Although overall length and branching density (as measured by fractal dimension and meristem numbers) of root systems were not related to root rot resistance, the lateral root number at the root: shoot interface was positively correlated with genotype tolerance (R 2 = 0.6*). Root diameter was also positively correlated with tolerance; this is consistent with the hypothesis that larger adventitious and basal roots are beneficial under disease stress. A field-based study of commercial snap bean cultivars compared raised and flat-bed systems of production, in a soil inoculated with Fusarium solani f. sp. phaseoli. Substantially greater yields (40% to 90%) were observed in raised beds. Root vigor was relatively high (root length density >0.2 cm·cm−3) and root rot scores were lower with raised than with flat-beds, in 2001, but not in 2000. Overall, this is suggestive that integrated crop management practices can improve lateral root vigor and reduce root rot severity.

Free access

Abstract

‘d’Anjou’ pears (Pyrus communis L.) harvested at optimum maturity, 6.4 kg flesh firmness, were stored in 0.5, 1.0, 1.5, 2.0, 2.5 and 5.0% O2 with CO2 concentration were maintained at 0.01 to 0.03%. Other samples were stored in commercially recommended concentrations of 2-2.5% O2 and 0.8-1.0% CO2 (i.e., regular CA), and conventional air storage. Temperatures of −1.1°C (30°F) were maintained in all cabinets throughout the 8 month storage. Oxygen concentration below 1.5% maintained the dessert quality of fruit and reduced the incidence of superficial storage scald after 8 months of storage. Fruit stored at 1.0% O2 for 8 months did not develop scald even after returning to air storage for 30 days. Oxygen concentration above 2% without CO2 had no beneficial effect on dessert quality or scald control. Regular CA storage also maintained dessert quality, but had only slight effect on scald control. Fruit stored below 2% O2 softened slower, lost titratable acids and free amino acids more slowly, and accumulated protein more slowly than samples stored at higher O2 levels for 8 months. Regular CA fruit changed similarly to those from the 1.0% and 1.5% O2 treatments. Overall fruit metabolism in 0.5% O2 was markedly retarded during the 5 to 8 month storage period.

Open Access

Abstract

Normal refrigeration (NR), low pressure (LP, 10 to 35 mm Hg), and low oxygen (0.5% to 8%) storage trials were conducted using cut flowers of carnation (Dianthus caryophyllus L.) and rose (Rosa sp.). Variables studied were storage time, gas partial pressures, vapor barriers, chemical pretreatments, grower source, cultivars, and stem recutting methods. Low oxygen storage was not beneficial regardless of variables tested. In general, carnations could be stored for 6 weeks under NR and 8 weeks under LP conditions if the flowers were pretreated with silver thiosulfate (STS) and vapor barriers were utilized during NR storage. Roses could be stored up to 2 weeks under NR and up to 4 weeks under LP conditions and still exhibit at least 61% of their nonstored, original vase-life if LP-induced leaf disorders were not considered. Rose vase-life after NR storage was enhanced by utilizing vapor barriers during storage, and visual appearance improved if stems were recut under water upon removal from storage. LP-stored roses did not benefit by these treatments. However, the same cultivars from different growers did not respond equally and great variability was noted among rose cultivars tested regardless of storage method. Of special concern were the LP-induced leaf disorders noted on ‘Forever Yours’, ‘Royalty’, ‘Town Crier’, and ‘Spanish Sun’ roses.

Open Access

Abstract

‘Bing’ sweet cherries (Prunus avium L.) harvested at commercial maturity were commercially packed and stored in 6 low-02 and 1 high-C02 controlled atmospheres (CA) at −1.1°C for 35 days and in a second study were stored in either 1.5% 02 and 0.8% C02 or 12% 02 and 10% C02 at 5.6°, 3.3°, or 1.1°C for 23 days. Fruit stored at 0.5–2.0% 02 with 0.03% C02 maintained a higher percentage of very green stems, brighter fruit color, and higher levels of titratable acids than those stored in air at −1.1°C for 35 days. High C02 atmospheres conserved fruit brightness and TA level but did not prevent stem discoloration. The only effect of lowering temperature from 5.6° to 1.1° was a slight increase in fruit firmness after storage.

Open Access