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Mary Jane Clark and Youbin Zheng

objective of this study was to determine the optimal fertilization rates for each of following three methods for #5 potted Vaccinium corymbosum ‘Duke’ production: organic substrate with organic granular (OG) fertilizer, organic substrate with organic

Open access

Thierry E. Besançon, Baylee L. Carr, and Albert Ayeni

, whereas the soil type at the Pittstown location was a Quakertown silt loam (fine-loamy, mixed, active, mesic Typic Hapludults) with a pH of 6.3 and 2.4% organic matter (USDA-NRCS, 2021). ‘NG3’ and ‘OG’ are the top two of several tigernut selections that

Free access

Alicia M. Borowski, Vincent A. Fritz, and Luther Waters Jr.

The objective of this study was to examine seed maturity at harvest as it relates to seed vigor in two commercial shrunken-2 (sh2 J sweet corn hybrids (Zea mays L. var rugosa Bonaf., cvs. Florida Staysweet, Crisp N' `Sweet 710). Seed harvest began at 0.76 g H2O/g fresh weight in 1987 and at 0.70 g H2O/g fresh weight in 1988 and 1989, and was continued at gradually declining moisture levels until frost. In five different tests of seed performance, seed of `Florida Staysweet' (FLASS) harvested between 0.23 to 0.57 g H2O/g fresh weight in 1987 possessed the highest seedling vigor. In 1988 and 1989, maximum vigor was achieved by FLASS seed harvested from 0.40 to 0.60 g H2O/g fresh weight and `Crisp N' Sweet 710' (CNS) seed harvested from 0.45 to 0.65 g H2O/g fresh weight. Standard germination test, seedling growth cold test (SGCT), and seed leachate conductivity provided the most consistent results to `determine optimum seed maturity. Seed weight was not as reliable an indicator of seed vigor in 1988 and 1989 as it was in 1987, and endosperm and embryo weights did not correlate with seedling vigor in any year.

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Alicia M. Borowski, Vincent A. Fritz, and Luther Waters Jr.

This study was conducted to determine if changes in the raffinose: sucrose ratio in embryos of shrunken-2 sweet corn (Zea mays L.) hybrids were related to differences in seed leachate conductivity between two hybrids harvested at four maturities and artificially dried to 0.10 g H2O/g fresh weight. The ratio of raffinose: sucrose differed for `Crisp N' Sweet 710' (CNS) and `How Sweet It Is' (HSII). The mass ratio of raffinose: sucrose in CNS was >0.3 in seed harvested between 0.44 to 0.64 g H2O/g fresh weight and increased as seed dried from the initial harvest moisture to 0.10 g H2O/g fresh weight. Raffinose: sucrose ratios of HSII were <0.3 at all harvests between 0.55 to 0.72 g H2O/g fresh weight, but changes during desiccation were not as pronounced. Leachate conductivity of whole seeds of CNS and HSII decreased as seeds were harvested at progressively lower moisture contents. We suggest that a higher raffinose: sucrose ratio may be indicative of increased seed vigor in shrunken-2 hybrids.

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J.A. Anderson, L.V. Gusta, D.W. Buchanan, and M.J. Burke

Abstract

Leaves of cold-acclimated lemon [Citrus limon (L.) Burm. f.], grapefruit (C. paradisi Macf.), orange [C. sinensis (L.) Osbeck], and mandarin (C. unshiu Marc.) trees ranged in cold hardiness from −4 to −11°C. No significant differences in water content (g H2O/g dry weight) or melting point depression were observed. Plots of liquid water content during freezing (g H2O/g dry weight) vs. temperature were similar for the 4 citrus species. The tissues apparently deviated from ideal freezing behavior because less ice was formed. The reduced ice formation could not be accounted for by osmotic effects. Negative pressure potential developed during freezing is hypothesized to play a role in tissue water potential in frozen systems. It was concluded that hardier Citrus leaves survive freezing of a larger fraction of their tissue water.

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Shibu M. Poulose, Edward D. Harris, and Bhimanagouda S. Patil

Limonoids are triterpinoids unique to citrus and neem trees with potential cancer-preventing properties in animals and human cell lines. Antioxidant activity and apoptotic induction are thought to be the principal effects of citrus limonoids in the antiproliferative properties, but this postulate lacks firm experimental evidence. In this study four highly purified 17 β-D glucopyranosides of citrus, limonin glucoside (LG), obacunone glucoside (OG), nomilinic acid glucoside (NAG), and deacetylnomilinic acid glucoside (DNAG), were tested for their effects against human SH-SY5Y neuroblastoma cells. Neuroblastomas account for 10% of childhood cancers, and in our study the cultured cells were treated with different concentrations and different time intervals. Micromolar levels of LG and OG significantly (P ≤ 0.001) stopped cell growth and induced cell death in 24 hours, but had no adverse effect over Chinese hamster ovary (CHO) cells at the highest toxic level tested. The viability studies were based on trypanblue exclusion and dimethylthiazol diphenyltetrazolium (MTT) reduction assays. The limonoids significantly increased the downstream caspases 3/7 activity (P ≤ 0.005) within 12 hours of treatment, suggesting an explicit role of apoptotic induction, which was confirmed by flow cytometry and DNA fragmentation assays. Highest S phase cell number was reduced by LG, followed by OG, NAG, and DNAG as compared to the known inhibitor camptothecin. Structural variations of limonoids could be ascribed to antioxidant activity. This study strongly supports apoptosis induction as an anticancer mechanism of citrus limonoids. Funded by USDA 2001-52102-11257 and 2004-34402-14768.

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O. Gulsen and M.L. Roose

1 Current address: Alata Bahce Kulturleri Arastirma Enstitusu, Erdemli-ICEL, 33740 Turkey. This paper is a portion of a MS thesis submitted by O.G. We thank Claire Federici, Robert Krueger, and Rainer Scora for advice and assistance and the Minister

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William B. Evans, Kenneth W. Hood, Peter M. Hudson, and Keri L. Paridon

Yield and economics of vegetable crops are being evaluated in non-adjacent organic (OG) and nonorganic (NOG) vegetable production field areas in Crystal Springs, Mississippi. Each production area has six sections in which crops are rotated over several seasons and years. Production techniques and management are as similar in timing and methodology as possible between the systems without compromising either system. Production methods, timing, and costs are recorded for each operation. These are combined with yield data to create budgets and estimated returns for each production system/crop combination. When possible, harvested produce is marketed by a cooperating grower-retailer at a local mid- to up-scale farmers market. Three years into the study, positive returns have been found for several crops including potato (Solanum tuberosum L.), lettuce (Latuca sativa L.), summer squash (Cucurbita pepo L.), cucumber (Cucumis sativa L.), and others. Marketable new potato yields in 2005 were under 10,000 lb/acre for Yukon Gold and Red Lasoda in either production system. Estimated net returns, based on an actual $2.00/lb market price, were positive for all system/cultivar combinations although final budget numbers are not firm. Significant differences in yield among cultivars were seen in potato, lettuce, summer squash, and cucumber. Organic production budgets for other crops in the study are also being developed.

Free access

O. Gulsen and M.L. Roose

1 Current address: Alata Bahce Kulturleri Arastirma Enstitusu, Erdemli-ICEL, 33740 Turkey. This paper is a portion of a MS thesis submitted by O.G. We thank Claire Federici, Robert Krueger, Rainer Scora, Mark Springer, and Richard Whitkus for advice

Free access

Dilip R. Panthee and Randy G. Gardner

attractive deep red color resulting from the recessive crimson gene ( Bc or og c ) in homozygous condition. Origin ‘Mountain Vineyard’ (tested as NC 10235) is the culmination of a tomato breeding effort initiated in 2002 to develop a superior hybrid grape