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Title: Improving disease control, yield and fruit quality in organic tomato production systems
Author: Theodoropoulou, Afroditi
ISNI:       0000 0004 2748 2409
Awarding Body: University of Newcastle Upon Tyne
Current Institution: University of Newcastle upon Tyne
Date of Award: 2009
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This study aimed to investigate and develop integrated crop management systems in organic glasshouse tomato production. The different management strategies that were used were tomato hybrid choice, grafting onto pest and disease resistant rootstocks, different fertiliser input types applied at several N-levels, steam disinfection of the soil substrate, chitin soil amendments and Milsana foliar disease control treatments. Four different experiments investigated the effects of these factors, as well as interactions between them, on the severity of a foliar disease Powdery mildew (Leveillula taurica), a soil-borne disease Corky root rot (Pyrenochaeta lycopersici) and nematodes infestation (Meloidogyne spp.). Tomato plant growth and yield parameters were also recorded in order to distinguish how the management practices that control plant pathogens affect growth and yield. Tomatoes are an important and significant source of nutrients and secondary metabolites which give a range of health benefits since many of the tomato micro constituents show antioxidative properties and have been linked with reduced risk of various forms of cancer and heart diseases. However, there is some evidence that the quality of tomato fruit is affected by hybrid choice, fertility management practices, grafting onto resistant rootstocks and the ripening stage at harvest. Therefore, tomato samples harvested from different trusses and at different ripening stages were analysed for quality parameters namely sugars, dry matter content and total antioxidant concentration. Of the two hybrids used in this experiment, Belladona plants grew slightly faster than 984 and produced many small fruit, while 984 plants produced fewer but bigger and heavier fruit. However, Belladonna and 984 did not show significant differences in their hydrophilic antioxidant activity although 984 fruit had higher sugar and dry matter content than Belladona fruit. Grafting onto the different rootstocks had beneficial effects on plant growth and reduced nematodes and corky root rot severity, but there were no significant effects on fruit antioxidants. The rootstock He-man F1 whilst shown to be more resistant against nematodes than R-5872 F1, was merely tolerant against corky root rot infection. On the other hand, the two rootstocks used had different effects on yield parameters. Grafting onto R-5872 F1 resulted in production of a larger number of smaller fruits, whilst grafting onto He-man F1 resulted in fewer, but bigger and heavier fruit.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available