Biology subjects

Teshome, A.

Publications and source records attributed to Teshome, A..

5 recordsLinked to original sources

bioRxiv2026

Large-scale phenotyping and multi-trait selection identify low-methane Napier grass (Cenchrus purpureus) accessions under contrasting environmental conditions

Abstract Napier grass (Cenchrus purpureus, NG) is an important forage in tropical and subtropical livestock systems, but the extent of naturally occurring variation in its methane (CH4) production and its potential for selecting low-CH4 emitting genotypes remains poorly characterised. This study evaluated variation in CH4 yield among NG accessions, examined the effects of season and water stress, validated contrasting CH4 phenotypes across donor cows, and identified elite accessions combining low CH4 yield with favourable digestibility. A total of 750 NG samples representing 84 accessions grown under dry and wet seasons and moderate and severe water-stress were evaluated using a high-throughput in-vitro fermentation system. To further identify forages combining low-CH4 production with acceptable digestibility, a multi-trait selection approach was applied using biologically defined thresholds for CH4 yield and in vitro organic matter digestibility (IVOMD), followed by a weighted index assigning 60% weight to CH4 yield and 40% to IVOMD. Methane yield varied widely among accessions, ranging from 0.02 to 5.07 mL/g DM and was affected by growing conditions. Methane production was generally lower during the wet season, while water stress was associated with changes in forage quality and fermentation characteristics. Low-CH4 producing accessions generally had lower IVOMD, crude protein and metabolizable energy and relatively higher fibre than high-CH4 producing accessions. Accessions initially classified as low and high-CH4 emitters based solely on CH4 yield were subsequently validated using rumen inoculum from three individual donor cows. Although the magnitude of CH4 production varied among donors, the contrast between low- and- high-CH4 accessions was generally retained, supporting the robustness of accession differences in CH4 production. Several accessions also maintained relatively low CH4 production across contrasting season and water-stress conditions, indicating that favourable CH4 phenotypes were not entirely environment dependent. A multi-trait selection identified ten elite accessions that produced 0.019-0.810 mL CH4/g DM and had 55.2-69.0% IVOMD, whereas ten poor-performing accessions produced 2.80-3.89 mL CH4/g DM and had 50.1-54.7% IVOMD. Differences in hexose fermentation and CH4 produced per unit of fermented substrate further indicated contrasting fermentation efficiency between the groups. These results demonstrate substantial variation in NG and identify accessions with low-CH4 production, favourable digestibility and relatively stable performance across growing conditions. In conclusion, incorporating CH4 yield and digestibility into forage selection could support the development of lower-emission forage cultivars for sustainable climate-smart livestock production.

plant biology↗

bioRxiv2024

Whole genome resequencing of a global collection of Napier grass (Cenchrus purpureus) to explore global population structure and QTL governing yield and feed quality traits

Napier grass (Cenchrus purpureus) is a C4 perennial grass species native to Sub-Saharan Africa (SSA), primarily used to feed cattle in SSA. In this study, we sequenced the genomes of 450 Napier grass individuals, sourced from 20 different countries. More than 170 million DNA variants (SNPs and Indels) were detected, of which [~]1% informative SNPs were used to assess genetic diversity in the collection. Our resequencing study provided valuable insights into the genetic diversity across a global Napier grass collection. Furthermore, a genome-wide association study on two independent populations, identified multiple quantitative trait loci (QTL) that were significantly associated with desirable agronomic traits, such as biomass yield, nitrogen and cellulose content. Therefore, our results will serve as a valuable resource in safeguarding and unravelling the patterns of Napier grass genetic diversity, in the face of climate change, and spearhead genomics-based breeding programs to develop high-yielding and drought-tolerant varieties suitable for forage and biofuel production.

plant biology↗

bioRxiv2024

Population genomics uncover loci for trait improvement in the indigenous African cereal tef (Eragrostis tef)

Tef (Eragrostis tef) is an indigenous African cereal that is gaining global attention as a gluten-free "superfood" with high protein, mineral, and fibre contents. However, tef yields are limited by lodging and by losses during harvest owing its small grain size (150x lighter than wheat). Breeders must also consider a strong cultural preference for white-grained over brown-grained varieties. Tef is relatively understudied with limited "omics" resources. Here, we resequenced 220 tef accessions from an Ethiopian diversity collection and also conducted multi-locational phenotyping for 25 agronomic and grain traits. Grain metabolome profiling revealed differential accumulation of fatty acids and flavonoids between white and brown grains. We conducted k-mer and SNP-based genome wide association and uncovered novel marker-trait associations. A significant 70 kb peak for panicle morphology contained the tef orthologue of rice qSH1, a transcription factor regulating inflorescence morphology in cereals. We also observed a previously unknown relationship between grain size, colour, and fatty acids. These traits were highly associated with retrotransposon insertions in homoeologues of TRANSPARENT TESTA 2, a known regulator of grain colour. Our study provides valuable resources for tef research and breeding, facilitating the development of improved cultivars with desirable agronomic and nutritional properties.

genomics↗

bioRxiv2023

A population genomics approach to unlock the genetic potential of lablab (Lablab purpureus), an underutilized tropical forage crop

BackgroundIn Sub-Saharan Africa (SSA) livestock production and productivity are severely restricted by the scarce supply of feedstuffs and forage crops, while those available are often of low nutritional quality resulting in poor animal productivity and leading to widespread malnutrition among the public, particularly women and children. Traditionally, several tropical forage crops have been used in the region both in the rangelands and as cut-and-carry cropping systems, but limited research attention has been paid to improve the quality of and access to these animal feeds. Lablab (Lablab purpureus (L.) is one of the conventionally grown multi-purpose underutilized crops that originated in Africa. It is an annual or short-lived perennial multi-purpose forage legume which has versatile uses (as a vegetable and dry seed), and as feed for animals, or as green manure. To develop new and highly productive lablab varieties, using genomics-assisted selection, the present study aimed to identify quantitative trait loci (QTL) associated with agronomically important traits in lablab and to assess the stability of these traits across two different agro-ecologies in Ethiopia. ResultsOne hundred and forty-two cultivated and wild lablab accessions displayed significant agro-morphological variation in eight analysed traits, including plant height, total fresh weight, and total dry weight. Further, the agronomic performance of the accessions was significantly different across locations and years, highlighting the substantial genotype-by-environment interactions. The population genetic structure of the lablab accessions, based on half a million high quality single nucleotide polymorphisms (SNPs), revealed an independent domestication pattern for two-seeded and four-seeded lablab accessions. Furthermore, based on multi-environmental trial data, a genome-wide association study (GWAS) identified useful SNPs and k-mers for yield-related traits, such as plant height and total dry weight. ConclusionsGenomic-assisted breeding is playing a key role in accelerating trait improvement in temperate forages, such as perennial ryegrass and alfalfa. Here we show that a similar approach could benefit underutilized crops such as lablab. The publicly available genomic tools and field evaluation data from this study will offer a valuable resource for plant breeders and researchers, to initiate genomic-assisted breeding in lablab which will fast-track genetic gain per unit time and ultimately contribute towards achieving food/nutritional security in the region.

genomics↗

bioRxiv2021

Insights into the genetic architecture of complex traits in Napier grass (Cenchrus purpureus) and QTL regions governing forage biomass yield, water use efficiency and feed quality traits

Napier grass is the most important perennial tropical grass native to Sub-Saharan Africa and widely grown in tropical and subtropical regions around the world, primarily as a forage crop for animal feed, but with potential as an energy crop and in a wide range of other areas. Genomic resources have recently been developed for Napier grass that need to be deployed for genetic improvement and molecular dissection of important agro-morphological and feed quality traits. From a diverse set of Napier grass genotypes assembled from two independent collections, a subset of 84 genotypes that best represents the genetic diversity of the collections were selected and evaluated for two years in dry (DS) and wet (WS) seasons under three soil moisture conditions: moderate water stress in DS (DS-MWS); severe water stress in DS (DS-SWS) and, under rainfed (RF) conditions in WS (WS-RF). Data for agro-morphological and feed quality traits, adjusted for the spatial heterogeneity in the experimental blocks, were collected over a two-year period from 2018 to 2020. A total of 135,706 molecular markers were filtered, after removing markers with missing values > 10% and a minor allele frequency (MAF) < 5 %, from the high-density genome-wide markers generated previously using the genotyping by sequencing (GBS) method of the DArTseq platform. A genome-wide association study (GWAS), using two different mixed linear model algorithms, identified more than 58 QTL regions and markers associated with agronomic, morphological and water-use efficiency traits. QTL regions governing purple pigmentation and feed quality traits were also identified. The identified markers will be useful in the genetic improvement of Napier grass through the application of marker-assisted selection and for further characterization and map-based cloning of the QTLs.

genetics↗