Phenotypic characterization and seed viability test in ex-situ conserved Ethiopian cultivated barley (Hordeum vulgare L.) landraces

BACKGROUND

Nowadays, most of the Ethiopian barley landraces had been lost from farmer's field and exclusively found ex-situ conserved at the Ethiopian Biodiversity Institute (EBI). Those ex-situ conserved are generally believed to be representative of the original population and possess high genetic diversity and important unique genes that are useful for tackling the various biotic and abiotic stresses in the face of the current climate change. Thus, this research was aimed at testing the performance of 150 ex-situ conserved landraces that had been collected from Arsi and Bale highlands, Southeastern Ethiopia. The landraces were tested at multiple test locations over two years (2021 and 2022).

RESULTS

All the tested landraces showed a good germination rate regardless of their long storage duration. In addition, performance of all the qualitative traits revealed a varying frequency for each character state. For example, most of the accessions (51.3%) had six kernel row numbers (KRN). All the remaining accessions had two rows (28.7%) and irregular KRN with variable lateral florets (20%). Likewise, some of the quantitative traits considered showed a significant variation among the landraces. However, there observed a significant variation for all the interaction effects in some of the traits considered signifying the importance of considering environment effects while targeting genetic selection and improvement of ex-situ conserved germplasms. The phenotypic coefficients of variation (PCV) were considerably high to medium in most of the traits considered including seed yield per hectare (SYPH) but with no associated higher genotypic coefficients of variation (GCV). Moreover, all the traits showed a far greater phenotypic coefficient of variation (PCV) to that of genotypic coefficients of variation (GCV) once again suggesting the pronounced effect of environmental factors to the variation. This was far supported by the significantly higher absolute magnitudes in phenotypic correlation compared to their corresponding genotypic correlation in most of the traits. Low estimates of heritability and genetic advance observed in all the traits considered except seed yield per hectare indicate importance of the trait for selection in Ethiopian barley improvement programs. Clustering patterns of the accessions, in narrow sense, revealed the existence of low divergence among the samples.

CONCLUSION

Ethiopian barley landraces are promising candidates for further yield improvement and conservation. However, further regular testing and screening should be conducted for the ex-situ conserved landraces because of the current erratic climate change. In addition, more robust molecular marker systems could be used to clearly reveal the extents of genetic diversity and to facilitate the breeding and conservation of Ethiopian barley landraces.

Optimized gamma radiation produces physiological and morphological changes that improve seed yield in wheat

To study the effect of gamma radiation on various morphological and agronomic characters of bread wheat (Triticum aestivum L.), seeds were subjected to different gamma radiation doses; and selected M₅ and M₆ generation lines were evaluated. The optimum doses to induce desirable changes in bread wheat were 100-200 Gy. Seed loss decreased while grain yield, yield components, fertile florets number, biological yield, plant height, harvest index and flag leaf area increased in all mutant lines. Shear strength increased in many lines. Selected mutant lines also showed reduced seed shattering that can greatly reduce seed loss at harvest. Some new phenotypic characters such as the appearance of bristles on the glume, important for drought tolerance, two spikelets at each rachis and more fertile florets at each spikelet. These can greatly increase yield, as seen in some mutant lines. Also, some physiological characteristics including photosynthetic rate, stomatal conductance, water use efficiency, and chlorophyll content improved in some mutant lines. About 95.8% of the total variation in grain yield was explained by three selected variables: flag leaf area, number of seeds per spike, and spike number per plant. Grain yield increased more than 45% in some mutant lines the highest ever reported using this approach to the genetic improvement of wheat. Wheat grain yield has increased 2.2 times in the last 50 years, which indicates that if mutagens are optimally used and the selection is carefully performed as described herein, it is possible to improve important economic traits, in a much shorter time.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-022-01225-0.

Introducing Explorer of Taxon Concepts with a case study on spider measurement matrix building

BACKGROUND

Taxonomic descriptions are traditionally composed in natural language and published in a format that cannot be directly used by computers. The Exploring Taxon Concepts (ETC) project has been developing a set of web-based software tools that convert morphological descriptions published in telegraphic style to character data that can be reused and repurposed. This paper introduces the first semi-automated pipeline, to our knowledge, that converts morphological descriptions into taxon-character matrices to support systematics and evolutionary biology research. We then demonstrate and evaluate the use of the ETC Input Creation - Text Capture - Matrix Generation pipeline to generate body part measurement matrices from a set of 188 spider morphological descriptions and report the findings.

RESULTS

From the given set of spider taxonomic publications, two versions of input (original and normalized) were generated and used by the ETC Text Capture and ETC Matrix Generation tools. The tools produced two corresponding spider body part measurement matrices, and the matrix from the normalized input was found to be much more similar to a gold standard matrix hand-curated by the scientist co-authors. Special conventions utilized in the original descriptions (e.g., the omission of measurement units) were attributed to the lower performance of using the original input. The results show that simple normalization of the description text greatly increased the quality of the machine-generated matrix and reduced edit effort. The machine-generated matrix also helped identify issues in the gold standard matrix.

CONCLUSIONS

ETC Text Capture and ETC Matrix Generation are low-barrier and effective tools for extracting measurement values from spider taxonomic descriptions and are more effective when the descriptions are self-contained. Special conventions that make the description text less self-contained challenge automated extraction of data from biodiversity descriptions and hinder the automated reuse of the published knowledge. The tools will be updated to support new requirements revealed in this case study.

Morphological and physiological comparison of taxa comprising the Sporothrix schenckii complex

Based on recent molecular data, it has been suggested that Sporothrix globosa is the main causal agent of sporotrichosis in China. The objective of this study was to compare the morphology, growth characteristics, patterns of carbon source usage, and susceptibility to antifungal agents among Sporothrix strains. A total of 15 clinical strains confirmed to be S. globosa, from three different regions of China, and 11 ex-type strains from the CBS-KNAW biodiversity center were obtained. The elongated conidia of S. pallida, S. variecibatus, S. schenckii, and S. schenckii luriei were clearly different from the subglobose and globose conidia of S. globosa strains. S. schenckii is able to assimilate sucrose, raffinose, and ribitol. Susceptibility profiles of these Sporothrix species were evaluated by measuring minimum inhibitory concentrations (MICs). Fluconazole, itraconazole, terbinafine, and amphotericin B showed good activity against most S. globosa clinical isolates from China. Potassium iodide also showed a low MIC against S. pallida, while fluconazole showed a high MIC for S. mexicana, S. humicola, S. globosa, S. schenckii, and S. inflata; these strains might be considered tolerant. The species showed differences in susceptibility to antifungal drugs and should therefore be properly identified during diagnosis prior to designing therapeutic strategies.