Transgenic `Rutgers' 37-81^ tomato (Lycopersicon esculentum Mill.) homozygous for a pectin methylesterase (PME) antisense gene, which lowers PME activity and increases levels of soluble solids, was compared to azygous (a segregating line of 37-81^ with 0 copies of the introduced gene) and wild-type `Rutgers' in the field during Summer 1992 and 1993 to determine the effects of the introduced PME antisense gene on tomato plant growth, fruit set, fruit yield, and fruit processing attributes. Fresh and dry weight accumulation in transgenic plants was similar to wild-type `Rutgers' and azygous 37-81^ lines during 1992 and 1993, indicating that the introduced PME antisense gene did not affect biomass accumulation. Transgenic plants showed an increase in fruit number and yield in 1992 compared to wild-type `Rutgers' and azygous 37-81^, but no differences were observed among the three genotypes in 1993. Average fruit weight did not show significant differences among the three genotypes in 1992, but was lower in azygous and transgenic plants than wild-type plants in 1993. Transgenic fruit had higher soluble and total solids and higher pH than control fruit, but shelf life was somewhat shorter in transgenic fruit. Overall, these data indicate that introduction of the PME antisense gene, which improves the processing quality of tomatoes, does not adversely affect fruit yield or vegetative growth of plants.
Denise M. Tieman, Kurt D. Kausch, Delila M. Serra, and Avtar K. Handa
Ravindranath V. Kanamangala, Niels O. Maness, Michael W. Smith, Gerald H. Brusewitz, Sue Knight, and Bhaggi Chinta
The unextracted and reduced lipid (supercritical carbon dioxide extraction of 22% and 27% (w/w) of total lipids) pecan [Carya illinoinensis (Wangenh.) K. Koch] kernels packaged in 21% O2, 79% N2 were analyzed for color, hexanal, sensory, fresh weight, and lipid class changes periodically during 37 weeks of storage at 25 °C and 55% relative humidity. Pecan nutmeats were lightened by partial lipid extraction. The pecan testa darkened (decreasing chromameter L*) with storage time. Most color changes occurred in the first 18 weeks. Hexanal concentration of reduced-lipid pecans was negligible throughout storage, while unextracted pecans reached excessive levels by week 22 of storage. Hexanal concentration, indicative of rancidity, was in agreement with sensory analysis results with the hexanal threshold level for objectionable rancidity ranging from 7 to 11 mg·kg-1 pecans. Weight change was negligible during storage, except in 27% reduced-lipid pecans. Free fatty acids increased with storage and were significantly higher in unextracted pecans than the reduced-lipid pecans at 0, 10, 18, 32, and 37 weeks of storage. Shelf life of pecans with partial lipid extraction was longer than unextracted pecans. In addition to decreasing the total amount of lipid available for oxidation, the free fatty acid lipid component that correlated with the development of rancidity was reduced by extraction.
Kim S. Lewers, John M. Enns, and Patricia Castro
with increased shelf life. Compared with other current cultivars and breeding selections evaluated after 2 weeks in cold storage, ‘Keepsake’ strawberries had a low proportion of degraded and decayed fruits. The fruits have outstanding flavor with high
John R. Stommel, Mary J. Camp, Judith M. Dumm, Kathleen G. Haynes, Yaguang Luo, and Anne Marie Schoevaars
, 2002 ). Tissue breakdown and microbial contamination are important problems that shorten product shelf life of pepper and other fresh-cut fruits and vegetables ( Barrett et al., 2010 ). Numerous factors contribute to fresh-cut product shelf life
Shahrokh Khanizadeh, Martine Deschênes, Claudine Dubé, Rong Tsao, Louis Gauthier, André Gosselin, and Yves Desjardins
‘Jeanne d'Orléans’ has larger and firmer fruits ( Fig. 1 ) that have an excellent shelf life and higher soluble solids compared with the commercial cultivars in this study. ‘Jeanne d'Orléans’ also has higher antioxidants than commercially grown raspberries
Titus M. Kyalo, H. Brent Pemberton, and Jayne M. Zajicek
To assess the effects of summer-like [high-temperature long-day (HTLD)] vs. winter-like [low-temperature short-day (LTSD)] growing conditions on production quality and postproduction longevity of potted miniature roses, plants of Rosa L. `Meirutral' and `Meijikatar' were grown in growth chambers using a short-cycle production schedule (potted liners grown until root establishment, pinched, and flowered). Plants grown under the HTLD environment [30C day/21C night plus 725 μmol·m–2·s–1 photosynthetic photon flux (PPF) for 14 hours per day] had more flowering shoots than those grown under the LTSD environment (21C day/16C night plus 725 μmol·m–2·s–1 PPF for 10 hours per day). The difference is attributable to fewer blind shoots (shoots with aborted growing terminals) under HTLD, because plants in both environments had the same total number of shoots at flowering. Plants in the HTLD chamber also flowered faster, were shorter, and had smaller and lighter-colored flowers than plants in the LTSD chamber. In addition, plants under HTLD exhibited greater poststorage floral longevity and whole-plant shelf life than plants grown under LTSD conditions, regardless of cultivar, simulated shipping (storage) treatment (4 days at 16C), or stage of floral development at harvest. These results suggest benefits from summer production of potted miniature rose plants and the possibility of using a higher-temperature forcing regimen than is normally recommended for winter production.
Karim M. Farag and Jiwan P. Palta
A natural lipid, lysophosphatidylethanolamine (LPE), was used as a tomato fruit ripening agent. The effect of this compound on hastening the ripening and on the defoliation of the `Heinz 7155' processing tomato and the Glamour fresh-market tomato (Lycopersicon esculentum Mill.) was compared to the effect of ethephon. Vines were sprayed to runoff in the field with a hand sprayer and fruits were harvested 2 weeks or 20 days later in a single harvest operation. LPE (100 mg liter-1) accelerated ripening of both processing and fresh-market tomatoes without defoliation. LPE-treated tomatoes had a better shelf life than the control or ethephon-treated fruit, whether they were harvested at the breaker, pink, or red stage of maturity. The combination of LPE and ethephon (100 mg liter-1) enhanced tomato ripening without damaging the foliage, suggesting that LPE can mitigate the undesirable effects of ethephon on foliage and the fruit. The LPE-related lipid phosphatidyldimethylethanol-amine dipalmitoyl (PDED) also was able to enhance some aspects of keeping quality of tomato fruits, but was not able to enhance fruit ripening. Phosphatidylethanolamine was not as effective as LPE or PDED. It appears that the active molecule of this natural lipid is the lyso form. Our results provide evidence that LPE can enhance tomato fruit ripening and postharvest storage life of vine-ripe fruits and fruits picked at early ripeness stages.
Randy G. Gardner and Dilip R. Panthee
other grape tomato cultivars. The rin gene of NC 2 Grape is useful in developing tomato hybrids with extended shelf life. Although rin is classified as recessive in action, it is not completely recessive and exerts influence in the heterozygous
James D. Hansen, Arnold H. Hara, and Victoria L. Tenbrink
Vapor heat treatments to disinfest tropical cut flowers and foliage were evaluated using a commercial facility. Efficacy was determined for specific durations against representative Hawaiian quarantine pests on their plant hosts. Nymphs and adults of aphids, soft and armored scales, mealybugs, and thrips were killed after 1 hour at 46.6C, and both life stages of aphids and armored scales along with mealybug nymphs after 2 hours at 45.2C. Injury to several varieties of Hawaiian floral commodities (Araceae, Musaceae, Zingiberaceae, Heliconiaceae, Orchidaceae, Marantaceae, Lycopodiaceae, Agavaceae, Proteaceae) during these treatments was determined. Large heliconias, most red ginger, bird-of-paradise flowers and leaves, and most foliage were not damaged; anthuriums, pincushion protea, and orchid flowers and foliage were very sensitive to vapor heat. Treatment modification was needed to reduce plant injury to these commodities without losing efficacy. The number of shelf-life days of the treated plant material was estimated from the visual ratings.
Gustavo H.A. Teixeira and José F. Durigan
short shelf life. Guava is a climacteric fruit exhibiting respiratory and ethylene peaks, which causes the guava to rapidly achieve senescence ( Nakasone and Paull, 1998 ). This makes the fruit inappropriate for consumption after a short period of time