Ethiopian mustard (Brassica carinata A. Braun), locally known as “Gomenzer” is an allotetraploid oilseed crop (BBCC, 2n = 34) that originated in the Ethiopian highlands through natural interspecific hybridization between Brassica nigra (BB) and Brassica oleracea (CC) [14]. It is one of the few crops domesticated in Ethiopia and has been cultivated for millennia as a dual-purpose species for edible oil and leafy vegetable production [1,6]. The crop is widely adapted to highland agro-ecologies (1700–2800 m a.s.l.) and plays an important role in smallholder mixed farming systems [2].

Globally, B. carinata is increasingly recognized as an emerging industrial oilseed crop due to its high biomass productivity, stress tolerance, and suitability for non-food applications such as biofuel production and sustainable aviation fuel [7, 12]. Its expansion into countries such as Canada, India, Australia, and Spain is driven by its favorable agronomic performance under low-input and marginal environments [13, 14]. Under improved agronomic conditions, yield potential ranges from 2.5 to 3.5 t ha⁻¹, although actual farm-level yields remain significantly lower due to genotype × environment interactions and management constraints [8, 10].

In Ethiopia, oilseed crops are an essential component of agricultural production and rural livelihoods. According to the Central Statistical Agency (CSA) Agricultural Sample Survey (2022/23 Meher season), oilseed crops occupy a considerable proportion of cultivated land, with Ethiopian mustard being one of the major Brassica oilseeds in highland areas [5]. However, national productivity remains low, with average yields of 0.9–1.2 t ha⁻¹ under farmer conditions, compared to 2.0–2.5 t ha⁻¹ under research-managed environments [5, 10]. This represents a yield gap of more than 50%, indicating substantial untapped production potential.

FAOSTAT data confirm that Ethiopia is among Africa’s leading producers of oilseed Brassicas; however, productivity growth has remained stagnant compared to global improvements in oilseed breeding and agronomic intensification [4]. Recent national assessments further indicate a declining production trend of Ethiopian mustard, from over 70,000 tons in 2011/12 to about 12,500 tons in 2020/21, mainly due to land-use competition, limited improved varieties, and weak input delivery systems [11, 12]. Smallholder fragmentation, low fertilizer use, and reliance on rainfed systems further exacerbate yield instability [12].

Despite these constraints, Ethiopian mustard possesses high agronomic and industrial value. The seed contains 27–40% oil, depending on genotype and environment [14, 15]. The oil is characterized by a high proportion of erucic acid (C22:1), often exceeding 40%, making it suitable for industrial applications such as lubricants, surfactants, cosmetics, and biofuel feedstock [12, 14] The seed cake contains 19–28% protein, although its utilization in livestock feed is limited due to high glucosinolate content [1, 3]. In addition, the leafy vegetable form is rich in vitamins A and C, minerals, and antioxidants, contributing significantly to household nutrition security in rural Ethiopia [4, 15].

Genetic studies have demonstrated substantial variability among Ethiopian mustard germplasm for yield, oil content, phenology, and stress tolerance, indicating strong potential for breeding improvement [1, 6, 9]. However, the number of officially released and widely adopted improved varieties remains limited, constraining productivity gains and farmer-level adoption.

Varietal registration is therefore a critical step in the crop improvement process, ensuring that candidate genotypes undergo rigorous multi-location evaluation and meet the standards of Distinctness, Uniformity, and Stability (DUS) and Value for Cultivation and Use (VCU) (OECD seed principles; CSA/EIAR variety release guidelines). The objective of this study was to register the released stable high yielding and good-quality Ethiopian Mustard variety for the highlands of Bale and other similar agro-ecologies.

2.     Origin and Varietal Evaluation

The Ethiopian mustard genotype ACC 20131 (“Malkaa”), along with 14 other genotypes, was obtained from the Holetta Agricultural Research Center under the Ethiopian Institute of Agricultural Research. Genotype ACC 20131 was identified as a promising candidate variety based on combined analysis of variance and comparative mean performance evaluations conducted across testing environments. Subsequently, the candidate genotype, together with the standard check varieties “Shaya” and “Yellow Dodola,” was evaluated in variety verification trials for potential release.

The trials were conducted during the 2022/23 main cropping season at two representative locations using plot sizes of 10 m × 10 m and were assessed by the National Variety Release Technical Committee. Based on its superior grain yield performance, yield advantage over the standard checks, and desirable level of resistance to major Ethiopian mustard diseases, including Alternaria leaf spot (Alternaria brassicae), Sclerotinia stem rot (Sclerotinia sclerotiorum), and white rust (Albugo candida), genotype ACC 20131 was officially approved and released as the variety “Malkaa.”

5. Varietal Characteristics

The newly released Ethiopian Mustard variety ‘Malkaa’ is characterized by its yellow flower color; the seed colors are Brown and Yellow. The average number of days required by the variety to reach its 50% flowering and 95% physiological maturity were 73 and 167, respectively, with the average plant height of170 cm. (Table 1).

6. Grain Yield Potential, Stability and Reaction to the Major Diseases

The variety “Malkaa” consistently demonstrated superior grain yield performance over the standard check varieties, Shaya and Yellow Dodola, across the 2018–2020 main cropping seasons at Sinana and Agarfa testing locations. Across all test environments, Malkaa ranked as the highest-yielding genotype among the evaluated entries, attaining an overall mean grain yield of 1,937 kg ha⁻¹. This represented a yield advantage of 31.21% over the standard check variety Shaya, indicating its strong yield potential and wider adaptation under the agro-ecological conditions of the study areas.

Disease reaction assessments further revealed that Malkaa exhibited a high level of resistance/tolerance to the major Ethiopian mustard diseases prevalent in the target production environments, namely Alternaria leaf spot (Alternaria brassicae), Sclerotinia stem rot (Sclerotinia sclerotiorum), and white rust (Albugo candida). Using the standard 1–9 disease severity rating scale, where lower scores indicate greater resistance, the variety recorded a mean disease score of 2 for all assessed diseases, reflecting its desirable disease reaction and field stability. Comparative disease reaction data for Malkaa and the standard check varieties (Table 2,3,4)

6. Quality Analysis

The Ethiopian mustard variety “Malkaa,” characterized by its attractive brown and yellow seed coloration, was highly preferred by both farmers and consumers due to its desirable seed appearance and superior oil yield potential. In addition to its market preference, the variety exhibited excellent oil quality attributes. Laboratory analysis conducted during the present study revealed that Malkaa possessed a high seed oil content of 47.36% (Table 1), indicating its strong potential for edible oil production and industrial utilization.

7. Performance Stability and Adaptation Domain

The Ethiopian mustard variety “Malkaa” was released for cultivation in the highland agro-ecologies of Bale, where it exhibited superior adaptation and performance under altitudinal ranges of 2300–2600 m above sea level and annual rainfall conditions of 750–1000 mm. The variety also possesses potential for wider production in other areas with comparable agro-climatic conditions. Based on multiple stability parameters evaluated across testing environments, Malkaa demonstrated relatively stable and consistent performance, indicating broad adaptability and reliable yield expression under varying environmental conditions (Table 1).

8. Variety Maintenance

The breeder and foundation seed are being maintained by Sinana Agricultural Research Center/ Oromia Agricultural Research Institute.

9. CONCLUSION

The present study demonstrated that the Ethiopian mustard variety “Malkaa” possesses superior agronomic performance, high grain yield potential, and elevated oil content across testing environments. The variety consistently outyielded the standard check variety, Shaya, with a yield advantage of 31.21%. Malkaa also exhibited stable field tolerance to major diseases, including Alternaria leaf spot (Alternaria brassicae), Sclerotinia stem rot (Sclerotinia sclerotiorum), and white rust (Albugo candida), indicating broad adaptation and production stability. Furthermore, its desirable seed characteristics, high oil yield, and suitability for mechanized production enhance its commercial value and seed multiplication potential. Therefore, large-scale promotion and cultivation of Malkaa could substantially contribute to improving Ethiopian mustard productivity, oilseed value chains, and market competitiveness.

10. ACKNOWLEDGEMENTS

The authors sincerely acknowledge the Oromia Agricultural Research Institute for financial support provided for the development and release of the variety. Special thanks are extended to the Pulse and Oil Crops Research Team of the Sinana Agricultural Research Center for their valuable contributions in field management and data collection. The authors also appreciate the support of the IQQO Food Science Research Directorate for oil content analysis and the Oil Crops National Research Program of the Holetta Agricultural Research Center for providing the germplasm used in this study.

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