Genetic variation for seasonal herbage yield, growth habit, and condensed tannins in Lotus pedunculatus Cav. and Lotus corniculatus L.

Abstract

Lotus pedunculatus (greater lotus) and L. corniculatus (birdsfoot trefoil) are perennial forages with potential to improve the legume content of pastures in south-eastern Australia. A collection of 39 accessions of each species was grown at 3 localities to assess the degree of genetic and genotype locality interaction components of variance for herbage yield, plant height, and width, the rate of reproductive development, and condensed tannin concentration as a prelude to forming strategies for genetic improvement. Rhizome development in L. pedunculatus and seed yields in both species were recorded at a single locality. The genetic variance component for herbage yield, plant height, and condensed tannins was significant for all characters, whereas the genotype × locality variance component was generally of lower magnitude. Grouping of accessions by geographic origin revealed important associations between characters. These associations were supported by strong positive genetic correlations. In L. pedunculatus, Portuguese accessions combined high autumn herbage yield with a tall plant type, a sparsely rhizomatous growth habit, high seed yield, and high condensed tannins. In L. corniculatus, prostrate growth habit was associated with high condensed tannins in accessions from Spain but was associated with low condensed tannins in Russian accessions. Principal components analysis of data for geographic groups of L. pedunculatus showed a positive association between means and variances, suggesting that selection within groups should be effective in producing cultivars with high herbage yield and low condensed tannins. In L.corniculatus, the positive genetic correlation between herbage yield and plant height suggested that hybridisation and selection would be required to produce a cultivar that would be more persistent under grazing.