Data from: Genetic diversity and population structure of Urochloa grass accessions from Tanzania using simple sequence repeat (SSR) markers

Urochloa (syn.—Brachiaria s.s.) is one of the most important tropical
forages that transformed livestock industries in Australia and South
America. Farmers in Africa are increasingly interested in growing Urochloa
to support the burgeoning livestock business, but the lack of cultivars
adapted to African environments has been a major challenge. Therefore,
this study examines genetic diversity of Tanzanian Urochloa accessions to
provide essential information for establishing a Urochloa breeding program
in Africa. A total of 36 historical Urochloa accessions initially
collected from Tanzania in 1985 were analyzed for genetic variation using
24 SSR markers along with six South American commercial cultivars. These
markers detected 407 alleles in the 36 Tanzania accessions and 6
commercial cultivars. Markers were highly informative with an average
polymorphic information content of 0.79. The analysis of molecular
variance revealed high genetic variation within individual accessions in a
species (92%), fixation index of 0.05 and gene flow estimate of 4.77
showed a low genetic differentiation and a high level of gene flow among
populations. An unweighted neighbor-joining tree grouped the 36 accessions
and six commercial cultivars into three main clusters. The clustering of
test accessions did not follow geographical origin. Similarly, population
structure analysis grouped the 42 tested genotypes into three major gene
pools. The results showed the Urochloa brizantha (A. Rich.) Stapf
population has the highest genetic diversity (I = 0.94) with high utility
in the Urochloa breeding and conservation program. As the Urochloa
accessions analyzed in this study represented only 3 of 31 regions of
Tanzania, further collection and characterization of materials from wider
geographical areas are necessary to comprehend the whole Urochloa
diversity in Tanzania.