Growth, psyllid resistance and forage quality of Leucaena leucocephala, L-pallida, L-diversifolia and the F1 hybrid of L-leucocephala x L-pallida

Sixteen accessions of Leucaena leucocephala, L. pallida and L. diversifolia and their interspecific hybrids were assessed for psyllid resistance, agronomic performance and forage quality in subtropical south-east Queensland. All accessions except the 4 L. leucocephala lines, L. diversifolia (K156) and its hybrid with L. Leucocephala (K8) exhibited moderate-high psyllid resistance, fast seedling growth, high dry matter production and cool tolerance. However, their forage quality, as indicated by in vitro dry matter digestibility and chemical composition, was inferior to that of L. leucocephala. Condensed tannin concentration, in particular, was higher in the non-L, leucocephala lines and this was associated with lower IVDMD and higher psyllid resistance. The implications for development of these lesser-known Leucaena species for forage use are discussed.