Investigation of two native Australian perennial forage legumes for their potential use in agriculture: Indigofera australis subsp. hesperia and Glycyrrhiza acanthocarpa

Abstract

In order to investigate the potential for domestication of native pasture legumes, a seed collecting mission was undertaken between Kalbarri and Esperance in the south of Western Australia followed by establishment of a field nursery at Northam, Western Australia. Indigofera australis subsp. hesperia Peter G.Wilson & Rowe was collected from eight sites, Indigofera brevidens Benth. from one site, and Glycyrrhiza acanthocarpa (Lindl.) J.M.Black from six sites. The field nursery was an irrigated, replicated trial designed to produce seed for future field testing and to provide preliminary information on plant agronomic characteristics. Over 12 months, I. australis produced herbage dry matter (DM) of 2.1–4.4 t/ha compared with 3.4 t/ha for a composite line of tedera (Bituminaria bituminosa C.H. Stirton vars. albomarginata and crassiuscula) and 1.0 t/ha DM for G. acanthocarpa. Most lines had digestibility and crude protein (15–25%) values that would support moderate growth of sheep or cattle. The best line of G. acanthocarpa produced >400 kg/ha of seeds, whereas I. australis had poor production most likely due to poor adaptation to the nursery site. The severity of cutting of I. australis plants had no significant effect on visual assessments of herbage growth. Most plants of I. australis died within 3 years, whereas most plants of G. acanthocarpa, I. brevidens and tedera survived for 3 years. Both I. australis and G. acanthocarpa have potential for use in broadacre agriculture as grazing plants, most likely in niches specifically suited to each, and demonstrate that native plants can contribute to pasture production currently dominated by exotic species.