DISAPPEARANCE OF CAPTAN FROM FIELD- AND GREENHOUSE-GROWN TOMATO FRUIT IN RELATIONSHIP TO TIME OF HARVEST AND AMOUNT OF RAINFALL

1987 ◽  
Vol 67 (1) ◽  
pp. 355-357 ◽  
Author(s):  
R. FRANK ◽  
H. E. BRAUN ◽  
G. RITCEY

Between 1982 and 1984 studies were conducted into captan disappearance from the fruit of field- and greenhouse-grown tomatoes (Lycopersicon esculentum L.). Captan was applied to field-grown tomatoes at 1.8 kg ha−1 a.i. in August 1982 and 1983, and to greenhouse tomatoes at 1.9 kg ha−1 in May 1983 and 1984. Initial residues in both cases were below 1.5 mg kg−1. Significant declines in residue occurred by day 2 (1983) or day 3 (1982) for field-grown tomatoes and residues were below 0.1 mg kg−1 by day 14 (1982) or day 15 (1983). The decline in field tomatoes was correlated with rainfall. With greenhouse tomatoes the residue did not significantly decline by day 15 in 1983 and significantly increased by day 15 in 1984.Key words: Tomato (field and greenhouse), Lycopersicon esculentum L., captan, residue decline

1991 ◽  
Vol 71 (3) ◽  
pp. 947-949 ◽  
Author(s):  
Athanasios P. Papadopoulos ◽  
Chin S. Tan

Three spring and two fall crops of greenhouse tomato (Lycopersicon esculentum L. Mill; various cultivars) grown in "Harrow" peat bags were irrigated 1, 4, 8 or 16 times daily. All plants received the same volume of fertilizer solution which varied with time from 0.2 to 1.0 L plant−1 d−1 according to crop and environmental conditions. The results showed little or no effect of irrigation frequency on early or total yield, number of grade no. 1 fruit, or fruit size. Key words: Lycopersicon esculentum, marketable yield


1991 ◽  
Vol 71 (3) ◽  
pp. 923-932 ◽  
Author(s):  
François Vézina ◽  
Marc J. Trudel ◽  
André Gosselin

Tomato plants (Lycopersicon esculentum 'Vedettos') were submitted to 10 light treatments obtained by modifying the supplemental photosynthetic photon flux (FPP) (0, 100, 150 μmol m−2 s−1), the photoperiod (natural, 14 h, 17 h, 20 h, 24 h) and the light distribution mode (one or two dark periods). Supplemental light was supplied by high-pressure vapor sodium lamps (HPS). Our results showed that supplemental lighting at a level of 150 μmol m−2 s−1 (PAR) helped to maintain a weekly yield of over 1 kg m−2 during November, December and January. Prolongation of the photoperiod over 14 h did not increase the yield. Plants exposed to continuous lighting were damaged even if they had been previously exposed to long photoperiods (17 and 20 h). For photoperiods of 17 and 20 h, lighting during the night which generated two dark periods per day damaged the plants and reduced the yields. Key words: Tomato (Lycopersicon esculentum), greenhouse, supplemental lighting, continuous lighting, yield, physiological disorders


1985 ◽  
Vol 65 (4) ◽  
pp. 1011-1018 ◽  
Author(s):  
C. S. TAN ◽  
B. N. DHANVANTARI

Two tomato (Lycopersicon esculentum Mill.) cultivars, Heinz-2653 and Campbell-28, were grown on Fox loamy sand in the subhumid region of southern Ontario from 1979 to 1982. Irrigation increased the marketable yields of H-2653 in a dry year, 1982, but not in the other years. Irrigation substantially increased marketable yields of C-28 in 1979 and 1982. Irrigation, when the available soil moisture (ASM) level reached 50%, was no more effective than when the ASM level in the soil was allowed to drop to 25%. Without irrigation yield increased as plant population increased in normal and wet years, but not in a dry year. Blossom-end rot (BER) of C-28 cultivar was markedly reduced by irrigation. Effects of irrigation or plant population treatments on the incidence of fruit speck did not appear to be significant.Key words: Available soil moisture, Lycopersicon esculentum, Pseudomonas syringae pv. tomato, fruit speck


1990 ◽  
Vol 2 (4) ◽  
pp. 243-254 ◽  
Author(s):  
Mandy J. Hetherington ◽  
Alan Martin ◽  
Douglas B. MacDougall ◽  
Keith R. Langley ◽  
Nick Bratchell

2002 ◽  
Vol 82 (2) ◽  
pp. 401-405
Author(s):  
N. A. Fairey

Seed of four grass species was re-hydrated to 11 pre-determined moisture concentrations ranging from 100 to 600 g kg-1 fresh weight ( FW) to simulate seed maturation during swathing and combining. The performance characteristics of three thermogravimetric and two electronic capacitance methods of moisture determination were evaluated. The thermogravimetric methods had no moisture range limitations and were, in general, more accurate than the electronic methods. The thermogravimetric Koster tester is suitable for grass seeds of all moisture concentrations, and can be easily adapted for use at field sites. The John Deere Moisture- Chek electronic tester is suitable for the rapid determination of moisture in grass seeds but is limited to concentrations of 80–250 g kg-1 FW. Key words: Grass seed crops, seed moisture measurement, swathing, combining, time of harvest


1970 ◽  
Vol 38 (2) ◽  
pp. 115-118 ◽  
Author(s):  
Ilkay Öztürk Çali ◽  
Feyza Candan

Effects of Agri Fos 400 (Mono and di-potassium phosphanate), a fungicide widely used on tomatoes grown in greenhouses in Turkey against Phytophthora infestans were studied on the morphology and viability of tomato (Lycopersicon esculentum Mill.) pollens. The fungicide was applied on tomato plants at recommended dosage (4 ml/l water) and double the recommended dosage (8 ml/l water). The fungicide caused changes in the morphological structures of pollens. Some pollen morphological structures that are not observed in the control group were encountered in the pollens due to application of Agri Fos 400 in equatorial view at 8 ml/l and in polar view at 4 ml/l. Level of pollen viability decreased as the dosage increased.   Key words: Fungicide; Phytophthora infestans; Tomato; Pollen morphology; Viability DOI: 10.3329/bjb.v38i2.5134 Bangladesh J. Bot. 38(2): 115-118, 2009 (December)


1975 ◽  
Vol 55 (2) ◽  
pp. 597-604
Author(s):  
W. R. ALLEN ◽  
K. C. CHADHA

A severe fruit disorder of tomato (Lycopersicon esculentum Mill.) was induced with a tobacco form of tobacco mosaic virus isolated from blemished tomato fruit (cv. Ohio WR25) from a glasshouse crop in southwestern Ontario. Symptoms on green tomatoes consisted of slightly sunken, pale or yellowish-brown lesions with a thin, dark green margin. Lesions frequently expanded and coalesced along the flutes. The shoulders of the fruit were the most extensively affected areas. On mature fruit, the lesions appeared either silvery or silvery-brown and generally had a scabby appearance due to cracking and lifting of the surface tissues. Lesions were superficial and internal symptoms were not detected. First-truss inoculations prevented or delayed the fruit disorder. Inoculations at truss stages two, three, and four, however, resulted in development of affected fruit on inoculated as well as lower and subsequent trusses with the exception of the first truss. Similar susceptibilities to the fruit disorder occurred among the glasshouse cultivars Michigan Ohio (Burghart strain), Ohio WR25, Vantage, Veegan, and Vendor. No cross protection against the fruit disorder was provided by a mild tomato form of TMV introduced at the second-leaf stage.


1992 ◽  
Vol 19 (2) ◽  
pp. 137 ◽  
Author(s):  
G Maclachlan ◽  
C Brady

Extracts of ripening tomato (Lycopersicon esculentum L. var. Sunny) were tested for their capacity to hydrolyse carboxymethylcellulose (CMC) and seed xyloglucan (XG) at different pH values in the presence or absence of seed XG oligosaccharide subunits (7 to 9 sugar residues). CMC-ase activities were most active at pH 5 and 7 in locule extracts, whereas XG-ase activity was most active in the presence of XG oligosaccharides at pH 6 in pericarp extracts. The cation exchange FPLC column, Mono S, separated three zones of CMC-ase activity in pericarp extracts. One zone was most active at pH 5, and two at pH 7. The three CMC-ases had some XG-ase activity in the presence of oligosaccharide but, in addition, there were two regions of the eluate with XG-ase but no CMC-ase activity. The presence of XG-ase activity, separate from CMC-ases, was also observed after hydrophobic interaction chromatography, and in protein precipitated by lowering the salt content of extracts. During ripening, the CMC-ases and the oligosaccharide-activated XG-ases in pericarp extracts increased in total and specific activities, while endogenous XG-ase activity, that is in the absence of XG oligosaccharides, remained unchanged or declined. It is concluded that multiple, 1,4-β-glucanase activities develop in ripening tomato fruit, including, in pericarp tissue, a specific XG-ase which is latent and activated by XG oligosaccharides.


1976 ◽  
Vol 56 (1) ◽  
pp. 133-137 ◽  
Author(s):  
G. M. WARD

Symptoms of sulphur deficiency and toxicity on greenhouse tomatoes (Lycopersicon esculentum Mill.) and cucumbers (Cucumis sativis L.) were produced experimentally in sand culture and are described in detail. The principal morphological effect was a general depression of growth and fruit production. A S content of less than 0.25% in any plant tissue was associated with severe deficiency. The distribution of S in various plant tissues is shown.


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