A new temperate forage legume with great potential - breeding new cultivars of Hedysarum

Abstract

Hedysarum coronarium (Sulla), H. carnosum and H. flexuosum have forage potential in the Australian cropping belt, being productive, non-bloating, and adapted to slightly acid to highly alkaline calcareous loam and clay soils. They are likely to benefit the environment by fixing large quantities of N, thus rejuvenating soil fertility and grain crop yield and quality. Sulla and H. carnosum are short-term perennial, deep tap rooted plants. Sulla varies in habit from prostrate to erect and is extremely productive (more than 20 t DM/ha in the second year). Lines vary widely in their abilities to set large quantities of seed. H. carnosum is an erect though less productive species, but is a heavy seeder. H. flexuosum is a productive, erect to semi-erect annual, and is a moderate to heavy seeder. H. carnosum flowers early, between 77-98 days, while the other species flower between 98-128 days. All are soft seeded, although they vary for this attribute.

Accessions with high DM and seed production in national evaluations (Qld and SA), and individual Sulla plants surviving dry conditions, root disease, and grazing (Qld) and with high dry matter and seed production attributes (AMGRC rows), are being used to develop synthetics; in Sulla, 18 prostrate and 13 erect synthetics with high DM and seed production, but differing flowering times and levels of hard seed, and two synthetics developed from plants surviving in a sward badly affected by Rhizoctonia solani ; and in H. carnosum and H. flexuosum, four and five synthetics respectively with higher dry matter and seed production and higher hard seed. Seed of these will be bulked for national testing in 2003 and 2004 for cultivar release and, if the breeding program is further resourced, recurrent selection.