Developmental patterns of flowers and pods and the effect on seed number in French serradella (Ornithopus sativus) and yellow serradella (Ornithopus compressus) cultivars

Context Reliable seed production is a key requirement for successful year-on-year regeneration of annual pasture legumes. Aims The study aims were to investigate the developmental patterns of flowers and pods and the effect on seed number among cultivars of French (Ornithopus sativus Brot.) and yellow serradella (O. compressus L.); and to assess the effects of early flower loss. Methods Four cultivars of each species were grown in a glasshouse under non-limiting growth conditions. Date of flowering and numbers of flowers, pods and seeds were assessed for up to 20 reproductive nodes on two stem axes per plant (n = 5 plants). A flower removal treatment was imposed to assess whether early flower loss affected flower and/or pod production. Key results Flowering in the serradellas was indeterminate, but for all cultivars there was a peak period of flower and pod production, with the timing and duration of the peak period differing among cultivars. Peak flowering occurred primarily because the proportion of plants flowering began to decline, but the number of flowers per reproductive node and the number of pods formed per node also declined with time. Compensation for early flower loss was observed for most cultivars because of a longer duration of pod formation and/or greater numbers of pods developed on higher reproductive nodes. Conclusions This study demonstrated that there is diversity in the patterns of flowering and podding and number of seeds initiated among serradellas. Implications Diversity in flowering and podding patterns combined with a capacity to compensate for early flower loss may be used to develop serradellas better able to cope with environmental stressors (frost, drought, heat) experienced during the flowering window.