Exploring Genome Diversity in the New Drought-Tolerant Perennial Pasture Legume Tedera (Bituminaria bituminosa) using Transcriptome-Derived Markers

Bituminaria bituminosa (L.) C.H. Stirt. is a perennial legume species originating from the Mediterranean region and Macaronesia. It is known as ‘tedera’ in the Canary Islands where it is traditionally grown as a drought-tolerant pasture species that provides valuable forage over the hot, dry summer season when few other pasture species produce any biomass. An Australian tedera breeding programme has been initiated to develop varieties adapted to Mediterranean-type regions of Australia. Germplasm available to the Australian tedera breeding programme comprised Spanish breeding lines and wild germplasm from the Canary Islands and the Mediterranean region. We conducted genetic diversity analyses of the available germplasm using microsatellite markers identified by sequencing a leaf transcriptome of a single breeding line. We confirmed the separation of three botanical varieties of B. bituminosa: vars. bituminosa, albomarginata and crassiuscula. We found evidence to support further division of var. bituminosainto two separate botanical varieties based on the region of origin (Canary Islands versus the Mediterranean region).

We are now developing a mapping population which we will genotype using next generation sequencing-derived markers in order to construct the first genetic map of this species and the first map of any species within the legume tribe Psoraleeae. This population will also be used to map important production and quality traits in the tedera genome. In this research we are developing important knowledge and genomic resources to assist the rapid development of tedera for the Mediterranean-type regions of Australia.