Centre for Plant Success Webinar Series: Daniel Otwani and Hanh Vo

Daniel Otwani

Exploring grain filling duration for yield in grain sorghum

Yield increase in sorghum has been achieved by increasing grain number. Scope exists to increase yield by changing grain size, however this has been limited by the negative association between grain size and grain number. Extending the grain filling duration (GFD) has potential to increase grain size without the trade-off with reduced grain number. This study aimed to:

• establish a replicable method to estimate GFD in sorghum
• establish the extent of genetic variation for GFD in sorghum
• establish the association of GFD with other yield determinants in sorghum and
• examine the putative value of an extended GFD to sorghum yield across environments

A diverse panel of 904 sorghum genotypes were evaluated in three environments across two years. An improved method of estimating GFD in sorghum is proposed, significant variation in GFD beyond current commercial sorghum hybrids reported, and a simulation of longer GFD and its impact on sorghum yield across Australian environments presented.

Hanh Vo

Identifying genes that are associated with rapid dehydration responses to low humidity

Humidity can vary significantly throughout the day and low humidity causes increased transpiration rate through stomatal pores. In response to low humidity, angiosperms can rapidly synthesise the stress hormone abscisic acid (ABA), which activates mechanisms preventing excessive water loss. Previous studies have indicated that within the ABA biosynthesis pathway, only the genes encoding the rate-limiting enzyme nine-cis-epoxycarotenoid dioxygenase (NCED) are significantly induced within the timeframe of stomatal closure. Despite their critical role, the genetic pathway responsible for the rapid upregulation of NCED genes remains uncharacterised.

To characterise the genes involved, we are using the model plant Arabidopsis thaliana. Plants were exposed to low humidity, and the physiological and gene expression responses at key time points were identified. This research aims to provide insights into the molecular mechanisms of plant stress responses, advancing our understanding of how plants survive in challenging and variable arid environments.

This event is open to Centre Members only. If you are a Centre Member who would like to attend, please contact admin@plantsuccess.org for the Zoom invitation.