Persistence, productivity and seed yield of Medicago murex, M. truncatula, M. aculeata and Trifolium subterraneum on an acid red earth soil in the wheat belt of eastern Australia

Abstract

The persistence, productivity, and seed yield of 4 annual legume species, Trifolium subterraneum L. var. subterraneum, Medicago murex Willd, M. truncatula Gaertn var. truncatula, and M. aculeata, were compared on an acid red earth soil at Temora. New South Wales. All species persisted for 4 years but there were significant differences in herbage yields and seed reserves between species, and between cultivars and lines within species. The recently released T. subterraneum cultivar, Junee, produced superior seedling densities in 2 of the 3 regenerative years and maintained similar summer seed reserves, but carried over a higher proportion of seed (hard seed) through each winter and was as productive as the older cultivar, Woogenellup, except in late spring. The 6 M. murex lines persisted and remained well nodulated on the moderately acid [pH(CaCl2) 4.81 soil when grown with a new acid-tolerant Rhizobium strain, WSM 419. Medicago murex demonstrated potential as an alternative species to T. subterraneum for the eastern wheat belt; it maintained high seed reserves and was more hardseeded than T. subterraneum cultivars, but this did not reduce its ability to produce large populations of seedlings in autumn. While the M. aceuleata and M. truncatula lines demonstrated that they could persist and regenerate adequately over the 4-year period, neither proved to be superior to either the T. subterraneum or M. murex lines in any of the parameters.