Low Nitrogen Narrows down Phenotypic Diversity in Durum Wheat

Abstract

Breeding for nitrogen use efficiency has become the major global concern and priority to improve agricultural sustainability. In an attempt to quantify genetic variation and identify traits for optimum and low N environments, 200 durum wheat genotypes were evaluated at three locations in the central highlands of Ethiopia during the 2020 growing season. The experiments were arranged in alpha lattice design with two replications. The results revealed significant differences among genotypes for all studied traits under both N conditions, indicating ample opportunities for genetic improvement. All traits except days to heading and maturity, grain filling period and grain protein content were higher under optimum than under low N. High values of genotypic and phenotypic coefficients of variations, broad sense heritability and genetic advance as percent of the mean were observed for number of fertile tillers and number of seed per spike (NSPS) under optimum, and spike length and NSPS under low N conditions. Cluster analysis classified the durum wheat genotypes into thirteen and eight clusters under optimum and low N, respectively. Principal component analysis detected five and four components which explained 81.29% and 73.63% of the total variations under optimum and N stress conditions, respectively. The present study confirmed the existence of wide genetic variability among the durum wheat genotypes under optimum and low N conditions; and low N lowers the level of diversity. Thus, our study paves the possibility for improvement of durum wheat genotypes through selection and hybridization for increased grain yield and adaptation to N stressed conditions.

Keywords:

• cluster
• durum wheat
• genetic divergence
• NDVI
• nitrogen efficiency
• principal components

Public Interest Statements

Durum wheat is one of the indigenous cereal species in Ethiopia. It has significant economic value and provides the raw materials for food industries in the nutrition of the global population and suitable for preparing traditional recipes in Ethiopia. However, the national productivity of the crop is far below the world average due to biotic and abiotic stresses resulted from global climate changes. Therefore, identification of genotypes performed well under the changing environmental conditions is mandatory to develop climate smart durum wheat varieties. Yield is a polygenic trait that is the result of numerous interrelated factors. Thus, understanding the relationships between traits and extent of genetic diversity in durum wheat is crucial to the success of durum wheat breeding programs in maximizing yield to feed the rapidly growing population.

Acknowledgments

The authors are grateful to the Ethiopian Institute of Agricultural Research (EIAR) and the International Maize and Wheat Improvement Center (CIMMYT) for financial support, as well as the Debre Zeit Agricultural Research Center for providing an experimental field.

Disclosure statement

No conflict of interest was reported by the authors.

Author contributions

Conceptualization, T.G; Methodology, T.G., F.A., K.A., T.B., and N.G.; Data curation, T.G, K.A., and T.B.; Formal analysis and software, T.G., T.B. and K. A.; Funding acquisition, T.G.; Resources, T.G.; Supervision, T.G., F.A., T.B., K.A., B.A. and N.G.; Visualization: T.G.; Writing-original draft, T.G.; Writing—review and editing, T.G., F.A., T.B., K.A., B.A. and N.G. All authors have read and agreed to the published version of the manuscript.

Data availability statement

The data presented in this study are available upon request from the corresponding author

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/23311932.2023.2197758.

Additional information

Funding

This research was funded by Ethiopian Institute of Agricultural Research (EIAR)

Notes on contributors

Tesfaye Geleta Aga

Tesfaye Geleta Aga is a researcher at the Ethiopian Institute of Agricultural Research; Debre Zeit Agricultural Research Center in Ethiopia for the last 10 years. He is currently pursuing a PhD in plant breeding and seed systems at Mekele University. He had conducted research on the adaptation of durum wheat to nutrient deficiency and acid soil tolerance. He is interested in studies that involve testing genotypes for nutrient use efficiency, abiotic stress tolerances and the generation of genetic variability using modern breeding tools. He is member of Ethiopian crop science society.