Genetic diversity and population structure among sorghum (Sorghum bicolor, L.) germplasm collections from Western Ethiopia

The Western Ethiopian region harbors a unique set of sorghum germplasm adapted to conditions not conventional to sorghums grown in other parts of the world. Accessions from the region possess unique resistance to multiple leaf and grain diseases. This study is aimed at exploring the extent of genetic variation and population structure among accessions of this region. A total of 123 accessions comprising 111 from Western Ethiopia (62 from Asosa and 49 from Pawe) and 12 U.S. adapted lines were genotyped using 30 sorghum simple sequence repeat markers (SSR). Genetic diversity and population structure were analyzed using PowerMarker and STRUCTURE software, respectively, based on 23 polymorphic SSR markers. Principal component analysis (PCA) was performed to view the variability in multi-dimensional space. Population structure analysis revealed considerable admixtures between Pawe and Asosa accessions, while the PowerMarker analysis grouped the accessions into three distinct clusters largely based on collection regions. The PCA did not clearly differentiate Asosa and Pawe accessions, but U.S. adapted lines were clearly separated from the rest. The study indicated the presence of marked genetic variability among accessions from Western Ethiopia and also provided clues on shared genetic events among accessions adapted to the two areas in Western Ethiopia.Keywords: Sorghum, genetic diversity, population structure, SSR, Ethiopi

A Large-Scale Genome-Wide Association Analyses of Ethiopian Sorghum Landrace Collection Reveal Loci Associated With Important Traits

The eastern Africa region, Ethiopia and its surroundings, is considered as the center of origin and diversity for sorghum, and has contributed to global sorghum genetic improvement. The germplasm from this region harbors enormous genetic variation for various traits but little is known regarding the genetic architecture of most traits. Here, 1425 Ethiopian landrace accessions were phenotyped under field conditions for presence or absence of awns, panicle compactness and shape, panicle exsertion, pericarp color, glume cover, plant height and smut resistance under diverse environmental conditions in Ethiopia. In addition, F1 hybrids obtained from a subset of 1341 accessions crossed to an A1 cytoplasmic male sterile line, ATx623, were scored for fertility/sterility reactions. Subsequently, genotyping-by-sequencing generated a total of 879,407 SNPs from which 72,190 robust SNP markers were selected after stringent quality control (QC). Pairwise distance-based hierarchical clustering identified 11 distinct groups. Of the genotypes assigned to either one of the 11 sub-populations, 65% had high ancestry membership coefficient with the likelihood of more than 0.60 and the remaining 35% represented highly admixed accessions. A genome-wide association study (GWAS) identified loci and SNPs associated with aforementioned traits. GWAS based on compressed mixed linear model (CMLM) identified SNPs with significant association (FDR ≤ 0.05) to the different traits studied. The percentage of total phenotypic variation explained with significant SNPs across traits ranged from 2 to 43%. Candidate genes showing significant association with different traits were identified. The sorghum bHLH transcription factor, ABORTED MICROSPORES was identified as a strong candidate gene conditioning male fertility. Notably, sorghum CLAVATA1 receptor like kinase, known for regulation of plant growth, and the ETHYLENE RESPONSIVE TRANSCRIPTION FACTOR gene RAP2-7, known to suppress transition to flowering, were significantly associated with plant height. In addition, the YELLOW SEED1 like MYB transcription factor and TANNIN1 showed strong association with pericarp color validating previous observations. Overall, the genetic architecture of natural variation representing the complex Ethiopian sorghum germplasm was established. The study contributes to the characterization of genes and alleles controlling agronomic traits, and will serve as a source of markers for molecular breeding

Genetic variability among lowland sorghum accessions collected from southern Ethiopia for grain quality traits

The study was carried out to assess the nature and magnitude of genetic variability for grain quality traits in lowland sorghum accessions. Understanding genetic diversity and trait association is crucial to designing an effective breeding plan to develop nutrient-rich varieties. Two hundred twenty-five accessions were evaluated using a simple lattice design with two replications at Weioto. Prepared samples per replication were scanned by mixing the grains and repacking the sample cup after each scan. Analysis of grain quality traits revealed significant (P ≥ 0.01) differences among the genotypes indicating a good chance for genetic improvement. Genotypic means of nutritional content showed that amylose (Am) content ranged from 19.11 to 20.80%, ash value ranged from 0.37 to 3.14%, starch content ranged from 42.29 to 72.77%, and protein (pr) in dry basis ranged from 2.62 to 10.45%. Similarly, iron (Fe) ranged from 1.38 to 73.21 ppm, zinc (Zn) ranged from 16.8 to 66.02 ppm, and tannin content ranged between -0.08 and 9105.21%. Broad-sense heritability (h2b) of all grain quality attributes such as amylose; ash; starch; moisture; iron; zinc; protein, and tannin was in the range of 13-92%. Principal component analysis showed the first three principal components with an eigenvalue equal to or greater than unity adequately explain the variation in the data. Significant positive genetic correlations (P < 0.001) with amylase, starch, iron, and zinc, while tannin had a weak association with grain yield. This result declares/signifies/a good prospect of southern Ethiopia lowland sorghum accessions for genetic improvement in grain yield and quality traits

Differences in temperature responses among phenological processes in diverse Ethiopian sorghum germplasm can affect their specific adaptation to environmental conditions

Background and AimsMain shoot total leaf number (TLN) is a key determinant of plant leaf area and crop adaptation. Environmental factors other than photoperiod can affect TLN in sorghum, implying that leaf appearance rate (LAR) and development rate can differ in response to temperature. The objectives of this study were to determine if (1) temperature effects on TLN can be explained as a consequence of differences in temperature responses across phenological processes and (2) genotypic differences in these responses can be linked to agroecological adaptation.MethodsNineteen sorghum genotypes were sown on twelve dates at two locations in Ethiopia with contrasting altitude, creating temperature differences independent of photoperiod. TLN and temperature were recorded in all experiments and LAR in six sowing dates.Key ResultsEleven of the genotypes showed a temperature effect on TLN, which was associated with a significantly higher base temperature (Tbase) for LAR than for pre-anthesis development rate (DR). In contrast, genotypes with no effect of temperature on TLN had similar Tbase for LAR and DR. Across genotypes, Tbase for LAR and DR were highly correlated, but genotypes with low Tbase had the greatest difference in Tbase between the two processes. Genotypic differences were associated with racial grouping

Διερεύνηση τεχνικών απαιτήσεων κωδίκων συστήματος για τη διασύνδεση υπεράκτιων αιολικών σταθμών με τεχνολογία συνεχούς ρεύματος υψηλής τάσης (HVDC)

Sorghum [Sorghum bicolor (L.) Moench] is an important dryland crop in the semiarid tropics, and temperature and photoperiod are the main environmental factors affecting its phenology and thus adaptation. The objectives of this study were to quantify the response of development rate to temperature and photoperiod for 19 diverse Ethiopian sorghum genotypes, and to determine if differences in these responses could be linked to racial grouping or agroecological adaptation. The genotypes, representing four major sorghum races and adaptation to four agroecological zones, were sown on 12 dates at two locations in Ethiopia with contrasting altitude. This created a range in photoperiod and temperatures relevant to Ethiopian conditions. Days from emergence to flag leaf appearance, anthesis, and maturity were recorded. A predictive phenology modeling framework was used to fit the effects of photoperiod and temperature on the rate of development for both the pre- and post-anthesis periods. Results indicated that the pre-anthesis development rate was independent of photoperiod for the range tested. This result differed from West African germplasm and likely reflects differences in agroecological adaptation and racial background. Significant genotypic differences were observed for the base temperature (0–9.8 °C) and for the optimum rate of development (0.011–0.022 d, with low value indicating late anthesis), with differences related to agroecology and racial type. Post-anthesis differences in the temperature response were minor. The observed differences in pre-anthesis base temperature can positively affect sorghum breeding programs globally, especially in temperate regions where suitability for early spring plantings is often restricted by low temperatures

Differences in temperature responses among phenological processes in diverse Ethiopian sorghum germplasm can affect their specific adaptation to environmental conditions

Main shoot total leaf number (TLN) is a key determinant of plant leaf area and crop adaptation. Environmental factors other than photoperiod can affect TLN in sorghum, implying that leaf appearance rate (LAR) and development rate can differ in response to temperature. The objectives of this study were to determine if (1) temperature effects on TLN can be explained as a consequence of differences in temperature responses across phenological processes and (2) genotypic differences in these responses can be linked to agroecological adaptation.Nineteen sorghum genotypes were sown on twelve dates at two locations in Ethiopia with contrasting altitude, creating temperature differences independent of photoperiod. TLN and temperature were recorded in all experiments and LAR in six sowing dates.Eleven of the genotypes showed a temperature effect on TLN, which was associated with a significantly higher base temperature (Tbase) for LAR than for pre-anthesis development rate (DR). In contrast, genotypes with no effect of temperature on TLN had similar Tbase for LAR and DR. Across genotypes, Tbase for LAR and DR were highly correlated, but genotypes with low Tbase had the greatest difference in Tbase between the two processes. Genotypic differences were associated with racial grouping.Genotypic and racial differences in responses of phenological processes to temperature, in particular in Tbase, can affect specific adaptation to agroecological zones, as these differences can affect TLN in response to temperature and hence canopy size and the duration of the pre-anthesis period. These can both affect the amount of water used and radiation intercepted pre-anthesis. A multi-disciplinary approach is required to identify genotype × environment × management combinations that can best capture the ensuing specific adaptation

Multi environment and spatial analysis of early maturing sorghum [Sorghum bicolor (L.) Moench] genotypes in dry lowland areas of Ethiopia

In Ethiopia, drought usually occur due to delay in onset, dry spell after sowing, drought during critical crop stage (flowering and grain filling stage) and too early cessation of rainfall. These situations can be addressed by developing improved sorghum varieties which are resistance to drought. Developments of sorghum varieties resistant to drought and producing better grain yield while addressing the plant biomass requirement is one of the strategies in the sorghum breeding program in dry lowland environment. A total of 90 early maturing sorghum genotypes were evaluated along with two standard check varieties to estimate the grain yield, plant height, days to flowering, days to maturity and overall agronomic aspects and stability of performance across the test environments. The trial was conducted using Randomized Complete Block Design (RCBD) in row and column arrangement. Linear mixed model has been used to predict and identify stable and superior varieties across the test environment. Correlations of the trials range from positive +1 to -1 where positive correlation is an indication of similarity among the testing environments while negative correlation is an indication of non-similarity among testing environments. Moreover, using the biplot it was observed that the stability and correlation among testing site where the angle between the two lines measure the strength of correlation. Improvement in heritability has been obtained due to spatial variation using advanced statistical analysis methods without any additional cost. Three genotypes exhibited better yield advantage, higher plant biomass and overall plant aspect including drought tolerance. In addition, these genotypes were preferred by farmers in their overall agronomic desirability (drought tolerance, earliness, head exertion and compactness, grain size and shape and threshability. Also, the national variety releasing committed has evaluated the variety verification trial both on station and farmers’ field condition in 2018/2019 and they decided the release of the candidate variety 14MWLSDT7114 (2005MI5060/E-36-1) for commercial production in dry lowland environment

Association between morphological traits and yield components in the durra sorghums of Ethiopia

Citation: Tesso, Tesfaye, Alemu Tirfessa, and Hussein Mohammed. “Association between Morphological Traits and Yield Components in the Durra Sorghums of Ethiopia.” Hereditas 148, no. 3 (2011): 98–109. https://doi.org/10.1111/j.1601-5223.2011.02229.x.The Ethio-Sudan region is recognized as the center of origin and diversity for cultivated sorghum. All major races of the crop are widely grown in Ethiopia with durras being dominant. The objective of the present study was to determine the extent of morphological variability among the Ethiopian durras and examine the pattern of relationships among these traits and their association with yield and yield components. Two hundred accessions collected from major sorghum-growing regions of the country were evaluated during the 2007 season at two locations representing hot and dry low land and mild mid-altitude environments. A randomized complete block design with three replications was used. Data were collected on phenology, plant height, a range of leaf traits and yield components. Significant variation was observed among all traits measured. Phenological traits and plant height were significantly correlated with each other and with all leaf traits. There was positive correlation among leaf traits, and between leaf traits and yield components except thousand kernel weight (TKW) and panicle length (PL). Grain fi ll duration was negatively correlated with all traits except days to maturity, TKW, and leaf length. Yield components except PL and TKW were positively correlated with each other. Selection that focuses on key yield components, larger leaf area, and on enhancing the grain filling rate by reducing excessive grain fill duration may contribute to yield improvement