Abstract/Summary

Pollen formation is considered ‘the Achilles tendon of reproductive development’. Therefore, special attention must be directed towards making sure that pollen is sufficiently robust, in order to cope with future climatic changes. One such anticipated future change in climate is increasing global temperature. Wheat is a very important crop for global food security, but wheat pollen development has been shown particularly sensitive to temperature stress. Therefore, work is needed to increase the environmental resilience of wheat pollen. In this thesis, attempts were made to not only find modern wheat varieties that had an increased tolerance to heat stress during pollen development, but also to clarify which stage(s) of wheat pollen development were the most sensitive to heat stress. Additionally, experimentation was conducted in order to assess the effect of heat stress on anther/pollen related gene expression, and the effect that inter-ear viable pollen movement had on yield restoration. In spite of it being shown that there were varieties that sustained significantly less grain losses, due to a heat stress event, and that a reduced level of pollen damage played a key role in this, it was apparent that this was not an example of tolerance, but instead an example of avoidance. Additionally, unlike previous reports, the developmental stage around pollen mother cell meiosis was not found to be the most significantly affected by heat stress, either in relation to grain number or microspore/pollen wellbeing. Instead, this designation was given to the latter stages of pollen wall development. Heat stress, during pollen development, had a profound effect on the expression levels/patterns of six anther/pollen related genes. This research has established a firm platform, in numerous different areas, for the future exploration of possibilities for reducing the effects of abiotic stress on wheat pollen development, and therefore directly increase yield resilience.