Please use this identifier to cite or link to this item: https://hdl.handle.net/1959.11/11430
Title: Effect of root diseases and drought on water use efficiency of wheat
Contributor(s): Aldahadha, Abdallah Mohammad Ali (author); Warwick, Nigel W (supervisor); Backhouse, David  (supervisor)orcid 
Conferred Date: 2012
Copyright Date: 2011
Open Access: Yes
Handle Link: https://hdl.handle.net/1959.11/11430
Abstract: In arid and semi-arid areas, wheat production is limited by drought mainly at the post-anthesis stage. Root diseases also affect the productivity of wheat. This work reports an examination of the response of wheat plants to the interaction of drought and root diseases. The major hypothesis was that root diseases reduce water use efficiency (WUE) under drought conditions. The preliminary experiment compared two cultivars, two root diseases and drought at two plant growth stages. There were no differences between the two root diseases, 'Pythium' and 'Rhizoctonia', however, there was reduced transpiration in diseased plants of cv. Janz following tillering drought, and of cv. Mulgara following anthesis drought. WUE was not affected by diseases. In experiments with deeper pots and post-anthesis drought treatment, 'Pythium' reduced transpiration prior to anthesis. When plants were regularly rewatered to field capacity before the post-anthesis drought, 'Pythium' had no effect on grain yield and WUE grain. When both infected and control plants were given the same total volume of water at high inoculum densities, infected plants had higher WUE grain than controls. Water uptake by infected roots was reduced during early plant growth due to root damage, but was higher than controls during post-anthesis drought due to higher remaining soil water availability, when compared with non-infected plants. However, diseased plants were not able to access all of the additional water and grain yields were not different from controls. Hydroponic experiments compared the effects of 'Pythium' and root pruning on plant water relations. 'Pythium', polyethyleneglycol-induced drought and root pruning reduced transpiration to a similar extent, but only 'Pythium' reduced shoot dry weight. 'Pythium' had no effect on total or instantaneous WUE. This experiment suggested that the effect of 'Pythium' was more than just in reducing the effective size of the root system. Root pruning at a late stage of vegetative growth in pots reduced WUE, demonstrating the importance of the stage at which root damage occurs on how it affects total WUE. Overall, root diseases did not reduce WUE. Reduction in growth was due to reduced transpiration. This did, however, lead to more water being available in soil during a post-anthesis drought.
Publication Type: Thesis Doctoral
Fields of Research (FoR) 2008: 070303 Crop and Pasture Biochemistry and Physiology
Fields of Research (FoR) 2020: 300404 Crop and pasture biochemistry and physiology
Socio-Economic Objective (SEO) 2008: 820507 Wheat
Socio-Economic Objective (SEO) 2020: 260312 Wheat
Rights Statement: Copyright 2011 - Abdallah Mohammad Ali Aldahadha
HERDC Category Description: T2 Thesis - Doctorate by Research
Appears in Collections:School of Environmental and Rural Science
Thesis Doctoral

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