Variation among strains of Phalaris tuberosa L. in nutritive value during summer

Abstract

Several plant characters related to the quality and yield of summer herbage were investigated in 21 Phalaris tuberosa strains and three P. arundinacea strains or hybrids grown as undefoliated spaced plants in the field. Significant variation existed amongst the strains in in vitro digestibility and protein content at the completion of the head emergence and seed ripening stages. Considerably more variation, of the order of four- to eightfold, existed in yield during the first winter, spring, and summer. Some strains were superior to the Australian cultivar in each of these characters, but no strain possessed high levels of all characters. By considering the range of variation exhibited by the plant characters, and their phenotypic correlations with other traits it was concluded that selection may be applied to the best advantage for higher yields of leaf lamina and higher digestibility and nitrogen content of stem and sheath after senescence, and for higher herbage production during summer. These changes would probably be accompanied by a delay in heading time and a reduction in stem yield. Direct assessment of the selected characters would be necessary, because none of them is closely correlated with other characters which could be measured more easily or at an earlier developmental stage.