Abstract Detail

Recent Topics Posters

Masters , Lizo Edward [1], Vorontsova, Maria S. [2], Zuntini, Alexandre [3], Tomaszewska, Paulina  [4], Heslop-Harrison, Pat [4].

Biodiversity and relationships of Urochloa grasses for application in sustainable tropical forage systems.

Urochloa (Brachiaria) grasses are among the most important forage crops in the tropics but are significantly under researched compared to forage grasses in temperate regions. Species from two agamic complexes (U. brizantha/ U.decumbens/ U. ruziziensis and U. humidicola/ U. dictyoneura) predominate agricultural systems but overlapping morphologies, hybridization/introgression events, and widely varying ploidy levels within the respective complexes contribute to unclear species limits. Urochloa crops also possess undesirable traits such as invasiveness, frost intolerance, and allelopathy. Breeding negative traits out of these grass crops requires that the evolution and species limits in Urochloa be better elucidated. This would allow for more sustainable farming practices to be achieved across tropical countries. We explored the phylogenomic relationships of agriculturally utilized Urochloa species using the Angiosperm 353 target enrichment kit on 118 transcriptomes and 9 genomes from specimens of Urochloa, closely related grass taxa, and outgroups. ASTRAL 5.7.7. was utilized to infer a species tree from the Angio353 dataset. Our results show that the two agamic complexes belong to well supported clades. Further, specimens of U. brizantha form a clade distinct from U. decumbens and U. humidicola. The latter two were grouped together in a supported clade. Similarly, a well-supported clade was formed containing U. humidicola and U. dictyoneura. Historically, the morphological characters separating U. decumbens from U. ruziziensis and U. humidicola from U. dictyoneura have been poorly correlated. Numerous taxonomists have argued that U. humidicola be lumped with U. dictyoneura, and that U. decumbens be lumped with U. ruziziensis. Our tree provides strong molecular evidence in support of these conclusions, as well as clear indications of species limits within the agamic complexes. These results allow for the characterization of the genetic resources in the genus and provide the foundation for exploiting germplasm diversity for breeding more sustainable Urochloa forages.

1 - Royal Botanic Gardens, Kew, Accelerated Taxonomy , Richmond , TW9 3AE, London, UK
2 - Royal Botanic Gardens, Kew, Department of Plant and Fungal Biology, Kew, Richmonnd, Surrey, TW9 3AE, UK
3 - Royal Botanic Gardens, Kew
4 - University of Leicester , Genetics and Genome Biology , University Road , LE1 7RH, Leicester, UK

Keywords:
Urochloa 
Brachiaria 
phylogenomics
Grasses
Angiosperm-353.

Presentation Type: Recent Topics Poster
Session: P1, Recent Topics Posters
Location: Virtual/Virtual
Date: Thursday, July 22nd, 2021
Time: 5:00 PM(EDT)
Number: P1RT029
Abstract ID:1419
Candidate for Awards:None