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Title: Film antitranspirants to increase yield of droughted wheat
Author: Weerasinghe, Minuka M.
Awarding Body: Harper Adams University
Current Institution: Harper Adams University
Date of Award: 2013
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Drought stress results in large yield losses in wheat. One way of alleviating the effect of drought stress on crops may be to suppress trans piration with antitranspirants. Film antitranspirants sprayed onto plants reduce transpiration by increasing the resistance to diffusion of water vapour from stomata, and are also of low permeability to carbon dioxide entering the leaf and thus photosynthesis and growth are restricted. Previous work has indicated that the most sensitive stage to wheat yield formation to drought stress, the stage of meiosis in pollen mother cells, may respond positively to film antitranspirant applications irrespec tive of reduced photosynthesis. The main objectives of this study were to determine the most effective growth stage to receive a film antitranspirant application targeted to increase yield under drought conditions and to explore the underlying mechanisms by which film antitranspirants increase yield. Field experiments were carried out in three consecutive years 2008/2009, 2009/2010 and 20 10 /20 11 under polytunnels. The experiments indicated that, among the growth stages included within the experiments (GS31, GS33, GS39, GS41 and GS59), GS33 is the most effective growth stage to apply film antitranspirants in order to increase yield of droughted wheat. There was a significant mean yield increase across all three years of 0.5 7 t/ha from fi lm antitranspirants, di - 1 - p - menthene and latex when sprayed at GS33 at SMDs above 66 mm, unde r the conditions of this study. T he yield increase by antitranspirant treatments was due to an increase in grains m - 2 either by increasing grains ear - 1 or tiller s urvival. The antitranspirant treatments significantly decreased transpiration, significantly increased leaf water potential and indicated a reduction in photosynthesis which was not significant. The antitranspirant treatments did not increase leaf temperat ure significantly. The antitranspirant treatments at GS33 and G S31 increased pollen viability. The observation of anthers using a light microscope collected from different growth stages showed that, in the variety Claire, meiosis in pollen mother cells occ ur s at early GS41. Therefore, the increased pollen viability by the antitranspirant treatments at GS33 may be attributed to an alleviation of the effect of drought stress on the crop during meiosis in pollen mother cells. The study performed to understand the effect of film antitranspirants on drought stress sensitive invertase genes, down regulated under drought stress did not show promising results may be due to a lack of representativeness of pollen/anther samples collected from different treatments. It was concluded that an antitranspirant treatment at GS33 can increase yield of droughted wheat by increasing grains m - 2 possibly via increased pollen viability at the stage of meiosis in pollen mother cells.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available