Mrs Laura Goward1,2, Rebecca Haling1, Rowan Smith2, Beth Penrose2, Dr Richard Simpson1
1CSIRO, Canberra, Australia, 2UTAS, Launceston, Australia
Biography:
Laura is a PhD candidate from the University of Tasmania (Tasmanian Institute of Agriculture) supervised by Dr Rowan Smith, Dr Beth Penrose, Dr Rebecca Haling and Dr Richard Simpson. She is externally based at CSIRO in Canberra.
Abstract:
Serradellas (Ornithopus spp.) are promising alternative annual legumes to subterranean clover (Trifolium subterraneum L.) for permanent, temperate pastures. However, some French serradella (O. sativus Brot.) cultivars exhibit unstable flowering dates. Not flowering at approximately the same optimal date each year increases the risk of plants being exposed to abiotic stressors (frost, heat, and drought) during flowering and seed development. This is a risk for annual legume persistence. Four French serradella genotypes were observed to flower at a similar time after late autumn sowing (May 2020) in Canberra (a cool temperate environment), but at different times when sown in early autumn (March 2020). In contrast, five subterranean clover genotypes exhibited relatively stable flowering dates (< 7 days difference in dates) irrespective of the sowing date. Flowering by these genotypes was subsequently examined in a controlled-environment experiment with different vernalisation treatments (0, 1, 3, 5, 7 or 9 weeks at 5 oC) followed by growth in different photoperiods (8 or 16 h) to assess whether differences in the length of vernalisation treatment needed to minimise time to flower were correlated with flowering date instability. The shortest vernalisation treatment from which no further response to increasing vernalisation duration was observed in the 8 h photoperiod treatment was negatively correlated with the flowering date stability indices observed in the field experiment (r2 = 0.76). French serradella genotypes sourced from environments where vernalisation plays a role in flowering time regulation are more likely to exhibit flowering date stability in temperate environments.