The first century of Phalaris aquatica L. cultivation and genetic improvement: a review

Abstract

2006 marked the centenary of the commercial propagation of phalaris (Phalaris aquatica L.) as a cultivated pasture plant, firstly in Australia, and soon after in New Zealand, South Africa, and North and South America. Small-scale evaluation of cv. Australian began in the Toowoomba Botanic Gardens, Queensland, in 1884. The first recorded large-scale production of seed was at the Glen Innes Research Farm of the NSW Department of Agriculture in February 1906. By 1908–15, several graziers in Australia and New Zealand sold seed widely within Australia, New Zealand, USA, Argentina, and South Africa. Factors affecting the utilisation of the original cultivar in Australia over the first half-century are reviewed. Thereafter, the need to extend the area of perennial pastures into regions unsuitable for cv. Australian led CSIRO and the US Department of Agriculture to collect germplasm widely in the Mediterranean region. Selection between and within Moroccan populations produced cvv. Sirocco and El Golea in Australia, and cv. Perla koleagrass in the USA. In Argentina, selection within cv. Australian produced the very successful, seed-retaining cv. Pergamino El Gaucho INTA, which was re-selected in Australia to produce cv. Seedmaster. The discovery of a single seed-retaining plant within a certified line of cv. Australian gave cv. Uneta, which had excellent seed retention because the rachillae of most seeds remained intact at maturity. In Australia, selection in populations derived from crosses between cv. Australian and Mediterranean ecotypes gave a succession of winter-active cultivars: Sirosa, Sirolan, Holdfast, Landmaster, Atlas PG, Advanced AT, and Holdfast GT. The latter 5 have Uneta-type seed retention, reduced tryptamine and tyramine alkaloids, and adaptation to different soil and climatic niches. Populations for the hotter, drier inland slopes of NSW are being field-tested. Also, a promising but unstable semi-dwarf line has been found: dwarfism appears to be caused by a transposable element. Breeding and selection programs in Argentina, several states of the USA, New Zealand, Israel, Tunisia, and Greece also produced cultivars with specific adaptations. Active breeding programs are continuing at Ardmore, OK, USA, and Pergamino, Argentina. A major remaining obstacle to the further improvement and utilisation of phalaris is the unknown chemical nature of the toxin(s) causing ‘sudden death’, which temporarily interfere with nitrogen metabolism in the brains of herbivores, especially ruminants.