Potatoes & drought stress: improving methods and investigating the utility of canopy traits to inform irrigation

Abstract/Summary

As an extremely drought susceptible crop, potato production is expected to be severely affected by climate change, due to the reduced seasonalrainfall predicted in many areas. To maintain or improve potato yields under these conditions, drought tolerant cultivars must be developed, irrigation infrastructure must be improved, and irrigation systems must become more efficient. However, potato is an under researched crop relative to the nutritional value it contributes to the food system. Of the research that has been conducted, many pot studies have likely been affected by the confounding effects of small pots on plant morphophysiology. Therefore, this thesis presents the first investigations of this effect in potato, demonstrating the cultivar-specific confounding effects of small pots on potato morphology. Further data show this is primarily a result of inadequate irrigation under supposedly well-watered conditions, diminishing the relative effects of water-restriction. These results provide methodological recommendations for further potted potato research, which were utilised in further experiments. These showed that canopy temperatures, but not SPAD values, reliably increase due to water-restriction in potted potato. It was also found that canopy temperatures return to baseline with the resumption of well-watered conditions, implying the potential for canopy temperatures to be integrated into a temperature-controlled irrigation system. Thus, the final study presented here investigates the efficacy of such a system. This system was limited by its sample size and by infection of the plants with blight, but it shows that the challenges threatening potato production may be mitigated with further investigation and refinement of similar systems.