Dr Brenton Leske1, Dr Ben Biddulph1, Prof Tim Colmer2
1Department of Primary Industries and Regional Development, South Perth, Australia, 2University of Western Australia, Crawley, 6009
Biography:
Brenton Leske is a research scientist at the Department of Primary Industries and Regional Development. His research for the last ten years has been on abiotic stress in cereal crops, with a particular focus on frost and cold stress. Breeding for frost tolerance has been a multi-decades-long challenge. There are stories of anecdotal evidence and theories, but today he will shed some light on progress in his presentation.
Abstract:
Frosts in winter and early spring can cause significant damage to cereal crops post-heading, reducing grain yield and quality. The interaction between how wheat spike morphology and plant structure may be related to abiotic stress, such as reproductive stage frost damage was explored. This study aimed to explore floret sterility in frost-damaged wheat spikes and potential interactions with spike morphology during field studies. To expose wheat plants to multiple natural frost events, field trials were established with multiple sowing times using a subset of four wheat cultivars known to vary in frost performance (from 60 commercial lines) with variation in awn length, spike length and plant height in 2018 and 2019. Main stem spikes were collected from field plots; plant structural traits and spike morphology (awn length, rachis gap and spike weight) were measured. Apical and basal spikelet awn lengths correlated with variation in frost damage in the subset of four cultivars (r2 = 0.29 to 0.80 and 0.20 to 0.98 respectively); central spikelet awn lengths had little to no correlation to floret sterility. Rachis gap initially appeared to correlate to floret sterility in four cultivars for a range of sowing times in 2018. However, there was no correlation in a wider sample size of 59 cultivars in 2018 and 46 cultivars in 2019 at the same site. Spike awn length and rachis gap did not correlate with variation in frost susceptibility to reproductive frost damage in wheat under field conditions. Improving wheat yields in frost-prone landscapes should focus on traits other than spike morphology, including variance in the ability to host ice-nucleating bacteria.