Genetic Diversity and Population Structure of Brachiaria (syn. Urochloa) Ecotypes from Uganda

Abstract

Brachiaria (syn. Urochloa) grass is an important tropical forage of African origin that supports millions of livestock and wildlife in the tropics. Overgrazing, conversion of grasslands for crop production and non-agricultural uses, and the introduction of improved forages have threatened the natural diversity of Brachiaria grass in Uganda. This study established a national collection of Brachiaria ecotypes in Uganda and analyzed them for genetic diversity and population structure using 24 simple sequence repeats (SSR) markers. These markers had a high discriminating ability with an average polymorphism information content (PIC) of 0.89 and detected 584 alleles in 99 ecotypes. Analysis of molecular variance revealed a high within populations variance (98%) indicating a high gene exchange or low genetic differentiation (PhiPT = 00.016) among the ecotype populations. The Bayesian model based clustering algorithm showed three allelic pools in Ugandan ecotypes. The principal component analysis (PCA) of ecotypes, and Neighbor-joining (NJ) tree of ecotypes and six commercial cultivars showed three main groups with variable membership coefficients. About 95% of ecotype pairs had Rogers’ genetic distance above 0.75, suggesting most of them were distantly related. This study confirms the high value of these ecotypes in Brachiaria grass conservation and improvement programs in Uganda and elsewhere.

Genetic parameters, prediction of selection gains and genetic diversity in Andropogon lateralis Nees ecotypes

“…Differences in the distribution of groups are a determining factor in the choice of parents and the difference in heterotic potential (Sant' Anna et al, 2021). Understanding genetic diversity available within naturally occurring ecotypes is important for a number of purposes, particularly genetic conservation and potential species improvement for desirable traits (Namazzi et al, 2020). Furthermore, by gaining more knowledge about the biological and ecological factors that can affect the distribution of genetic diversity among, and within, populations of a given species over time and space are fundamental for the successful implementation of management and conservation strategies (Liddell et al, 2020).…”

“…It also lowered the distortion and stress, which minimized the deformation of the dendrogram. The PCA method has previously been used to characterize accessions within germplasm banks for species including Urochloa (Namazzi et al, 2020), Emmenopterys henryi Oliv (Niu et al, 2021), Passiflora spp. (Jesus et al, 2022), Pinus bungeana (Tian et al, 2022), Glycyrrhiza uralensis (Dang et al, 2022), and Zea mays L. (Badu-Apraku et al, 2021).…”

An Overview of the Genetics and Genomics of the Urochloa Species Most Commonly Used in Pastures

“…A national collection of Urochloa ecotypes from Uganda, possibly represented by different species, was evaluated using 24 SSR markers ( Namazzi et al, 2020 ). These markers had a high discriminating ability with an average polymorphism information content (PIC) of 0.89 and detected 584 alleles in 99 ecotypes.…”

Forage Grasses Steer Soil Nitrogen Processes, Microbial Populations, and Microbiome Composition in A Long-term Tropical Agriculture System

“…Panicum) and Urochloa (syn. Brachiaria), Urochloa is notable for its low soil fertility demands and great adaptability in tropical regions (Canisares et al, 2021;Crusciol et al, 2020;Namazzi et al, 2020). Urochloa spp.…”