Investigation of plant-environment interactions affecting high temperature induced reductions in cropping in everbearing strawberries (Frageria x ananassa Duch.)

The work in this project aimed to shed light on the basis of high temperature induced reductions in cropping in everbearing strawberries. This would enhance the understanding of the physiology of this response in everbearing strawberries, and contribute to the development of practical methods to alleviate its severity on a commercial scale. Two physiological components have been revealed by the research: first, the reduction in flower production following a high temperature episode. Secondly, post-anthesis flower abortion and the potential importance of pollen performance. In flowers which were emerging under high temperatures, pollen showed reduced germination capacity. This is suggested to be a contributory factor to the observed post-anthesis flower abortion, which resulted in significant proportions of flowers not setting fruit. As a result, the final crop did not reflect the number of flowers produced by the plant and there was a high temperature-induced cropping trough. As far as practical methods are concerned, the interaction of other environmental factors with temperature was not found to alleviate the adverse effects of high temperature on cropping. The factors studied were vapour pressure deficit in the growth environment, and osmotic potential of the substrate (electrical conductivity of the feed solution). Crop load reduction (Le. truss removal) was also studied as a potential means of alleviating high-temperature induced cropping troughs, but the cropping patterns of treated plants did not differ significantly from those of the non- treated plants. Finally, poly tunnel cooling technologies were evaluated and it was found that forced air ventilation incorporated into a tunnel with a light diffusive cladding material with a degree of internal shading up to 35% could provide temperature control. This therefore could provide the potential to reduce temperature inside polytunnels and so ameliorate cropping troughs following periods of high summer temperatures.EThOS - Electronic Theses Online ServiceGBUnited Kingdo