Variation in flowering time and flowering date stability within a cultivar of French serradella

ABSTRACT Context. Opportunity exists to expand serradella (Ornithopus spp.) use onto heavier, duplex soil types in permanent pasture environments of south-eastern Australia. This requires cultivars with appropriate flowering times and flowering-date stability (i.e. flowering at the same date in spring regardless of timing of the autumn break). Aim. This work examined evidence of variation in flowering date and flowering-date stability in the NSW southern tablelands for a widely-used French serradella (O. sativus) cv. Margurita. Methods. Seed (sourced from a commercial supplier) was sown 21 March 2019 (Canberra, ACT) and 231 individual plants were monitored for time to first flower. A subset of plants exhibiting ‘early’ or ‘late’ flowering were identified and their seeds collected. In 2020, seed from ~15 plants from each selection was sown in Canberra in late March and early May to represent an ‘early’ and a ‘later’ break of season (n = 3). Key results. In the early-sown treatment, ‘early-flowering’ selections typically reached the median date of first flower (50%-flowering) from mid- to late August, while ‘late-flowering’ selections reached 50%-flowering early- to mid-September. When sown later, the ‘early-flowering’ selections began flowering from mid- to late September, while the ‘late-flowering’ selections flowered mid-September to early October. The ‘early’ selections exhibited greater flowering-date instability than ‘late’ selections and flowered particularly early when sown early. This indicated diversity within cv. Margurita for flowering-time control (e.g. vernalisation and/or photoperiod requirements). Implications. Evaluating cultivars of serradellas for flowering date and flowering date stability in their target environment(s) is essential to ensure cultivars are suitably adapted to these environments.