Sustainable agricultural production entails growing food without damaging the underlying soil. Legumes are of great interest for such efforts: because they produce their own nitrogen via symbiotic nitrogen fixation, legumes can actually improve the soil.
Among legumes, pasture or forage legumes tend to be more resilient to stress and more capable of thriving in marginal land. These forage legumes are highly valued feed for extensive livestock production. There is an increasing interest worldwide in using annual forage legumes as cover crops to supply soil nitrogen. Symbiotic nitrogen fixation in legumes leads to high protein fodder content and rejuvenated soils for a sustainable feed system.
Clovers are among the most effective to break the ‘infernal circle of the fallow’ a technique known to the Germans as ‘Besömmerung’. Subterranean clover (Trifolium subterraneum L.) makes the greatest contribution to livestock feed production and soil improvement in terms of total worldwide usage among annual clovers, particularly in Australia, where it is sown over 29 million hectares. The self-reseeding ability and grazing tolerance of subterranean clover, even under suboptimal and variable environmental conditions, contribute to its widespread distribution.
Subterranean clover is a diploid (2n = 2x = 16), predominantly inbreeding, annual species with a relatively small genome size of 540 Mbp (1C = 0.55 pg DNA) that can be readily hybridized, and exhibits wide diversity for both qualitative and quantitative agronomic and morphological characters. Within the genus Trifolium, it is established as a reference species for genetic and genomic studies.
Today, we add the subterranean clover chromosome-length resource to the DNA Zoo website. The assembly is described in more detail in our 2018 preprint on the subject.
The Hi-C work was enabled by resources provided by DNA Zoo Australia, The University of Western Australia (UWA) and DNA Zoo, Aiden Lab at Baylor College of Medicine (BCM) with additional computational resources and support from the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia. The following people contributed to the Hi-C chromosome-length upgrade of the project: Christopher Lui, Melanie Pham, Olga Dudchenko, Erez Aiden & Parwinder Kaur.