PhD study moves Ethiopian sesame research forward
The potential for boosting the production and sales of sesame in Ethiopia and internationally appears to be huge — if current production and market constraints can be overcome. Sesame is the second-most valuable export crop for this country, after coffee, despite yields being relatively low.
These low yields are attributed to the lack of high-yielding and well-adapted varieties with capsule-shattering tolerance and resistance/tolerance to biotic and abiotic stresses. A lack of modern crop production technologies and well-developed infrastructure are also significant.
Breeding work done by ACCI student Dr. Desawi Hdru for his PhD thesis, completed this year, offers hope for farmers that improved yields may be possible.
Hdru comes from Adi Arbaete (Rama), a district of the Tigray region in northern Ethiopia, where he grew up working on the family farm. “Farmers in our community were selecting and tagging vigorous plants with big heads of sorghum and cobs of maize,” he recalled in an interview.
“They selected the best plants, retained the seeds for the next planting season and preserved (harvests) traditionally by exposing the seeds to smoke to reduce storage insect pest damage. I was inspired by the indigenous knowledge and skills of my parents and the community, and this motivated me to become a plant breeder” he said.
Hdru completed a bachelor’s degree in Plant Sciences in 2006 at Alemaya University, and a master’s degree in Plant Breeding in 2014 at Jimma University in Ethiopia. His master’s and PhD studies were both on sesame. His PhD thesis focused on pre-breeding for improved yield and oil quality and quantity in Ethiopia. This study was supervised by the ACCI’s Professor Hussein Shimelis with an in-country co-supervisor, Dr Abush Tesfaye.
“I was a researcher and member of the national sesame coordination team based at the Humera Agricultural Research Centre for seven years,” he explained about his choice of thesis topic. Hdru was part of a team that released two new sesame varieties for Ethiopia, namely: Hemera-1 and Setit-1, choosing the focus of his PhD because he wanted to broaden the knowledge and skills required to breed sesame and other crops, to serve the value chains.
His study started with a participatory rural appraisal (PRA) involving 160 farmers in two selected sesame-growing regions and four districts in Ethiopia. Sesame production opportunities and constraints were documented, as well as farmer- and market-preferred varieties and traits, in eastern and southwestern Ethiopia, as a guide for breeding and large-scale production.
Next, he evaluated 100 Ethiopian sesame genotypes to determine the various genetic components, broad-sense heritability and association of seed and oil yield-related traits. Hdru also profiled these 100 genotypes using 27 polymorphic SSR markers, to determine the extent of genetic diversity among them.
For this he used diverse phenotypic traits and 27 simple sequence repeat (SSR) markers to select distinct and complementary genotypes for breeding. The molecular genetics work was done at the Oil Crops Research Institute of the Chinese Academy of Agricultural Science, based on research collaboration between the two countries. Also, near-infrared reflectance spectrometry (NIRS) was used to determine the contents of the seed oil and fatty acids of the 100 sesame lines.
In addition to completing his PhD this year, Hdru had the satisfaction of seeing five of his research papers published in high-impact journals and one paper featured in Encyclopedia.pub as a new entry on sesame.
Hdrui also recalled the challenges of the last few years. He was isolated from his loved ones for the last three years due to instability in the region, and his wife and three-year-old daughter are still in Tigray. He describes how more than 1 000 F1 sesame progenies that he developed from selected parents’ crosses and planted at Humera Agricultural Research Center could not be harvested because of conflict in that area. His research was also affected by the lockdown and travel restrictions due to Covid-19. Despite these hardships, he persisted and completed his PhD studies with excellent outputs.
Shimelis applauded Desawi for his tenacity, hard work and focus on his studies. He said Hdru’s research contributed to the ongoing sesame research and development in Ethiopia. His research pinpointed the major production constraints currently affecting farmers, as well as the preferred varieties and traits of sesame. This will serve as a guide for future large-scale production and breeding. The study also identified the genetic profiles and resources of sesame for breeding in Ethiopia and elsewhere. Hdru has selected unique sesame lines with high seed yields and better oil content and quality traits.
Hdru is currently working at the Ethiopian Agricultural Transformation Institute on oilseed crops, and he looks forward to regional and international research collaborations and opportunities on sesame breeding and genetics.
He thanked his supervisor and the organisations that helped him for their support, especially the Agricultural Transformation Institute.
Words: Shelagh McLoughlin