Promising findings open new avenues for sorghum research
A keen interest in tackling critical challenges, like climate change and food insecurity in Africa, led Asande Ngidi to focus on sorghum for his master’s thesis. The findings of his assessment of selected genotypes for agronomic performance, biomass production and carbon accumulation were significant, and have put him on the path to furthering this research in a PhD.
Sorghum, an indigenous African plant, is a crucial food and feed crop in dry regions of the world. Features like powerful roots that grow to three to five metres, and the ability to become dormant during droughts, mean it can survive where many other crops can’t.
Ngidi grew up in Nongoma, KwaZulu-Natal in South Africa. After his bachelor’s degree, he was inspired to study plant breeding by his “deep-rooted connection to agriculture and the influence of my upbringing in a rural, traditional Zulu family. Growing up in Nongoma, I was surrounded by the rich agricultural landscape and witnessed firsthand the importance of crops and farming in our community.”
“My parents always encouraged me to pursue my interests, and I was particularly drawn to the idea of improving crop yields and sustainability. The possibility of contributing to food security and enhancing agricultural practices motivated me to delve deeper into the field of plant breeding,” he said.
His master’s degree focused on screening sorghum genotypes to identify those with better agronomic traits, biomass allocation, and carbon storage. These traits would enhance soil health and fertility, boost sorghum production, improve food security, and ultimately help mitigate climate change.
“Sorghum is a vital crop in many African counties, known for its resilience to harsh conditions,” he said. “By focusing on this crop, I aimed to explore how different genotypes could contribute to better agronomic performance, improved biomass distribution and enhanced carbon storage. These factors are crucial for improving soil health and fertility, increasing sorghum production, and ultimately supporting food security and climate change mitigation efforts.”
Ngidi’s research began in February 2022 with 50 sorghum genotypes identified for high grain yield, biomass, and ethanol production. The sorghum genotypes were planted in three locations (Ukulinga at UKZN, Silverton in Pretoria, and Bethlehem in Free State) during the 2022/2023 growing season.
Data collected were plant, shoot, and root biomass, root-to-shoot biomass ration, grain yield, and harvest index. The sorghum at Silverton was harvested in August 2022 and the sorghum at Ukulinga and Bethlehem was harvested in April and May 2023.
After harvest carbon analysis was done on the sorghum grown at Silverton. This involved collecting shoot, root and grain biomass samples to determine the carbon content of each. These samples were dried and transformed into fine powder, weighing five grams each. The total carbon content of the shoot, root, and grain samples was determined by combustion. The carbon content for each sample was then converted to carbon stocks. “Data analysis was done, and we were able to identify genotypes that had high grain yield, biomass production, and carbon storage for production and breeding,” said Ngidi.
This data collected from the field experiments was then used to calculate the variance components, heritability and genetic advance to assess the extent of genetic variability for agronomic and carbon storage traits in selected sorghum genotypes. This allowed the best candidates for production or breeding to be identified.
Lastly, correlation and path coefficient analyses were computed to assess the trend and magnitude of associations of several traits, to guide simultaneous selection for enhanced grain yield, its components and carbon storage.
The project was challenging. “Managing field trials effectively required meticulous planning and coordination, particularly given the variability in weather conditions and the need for consistent monitoring and data collection,” said Ngidi. There were exciting moments too. Some sorghum genotypes had relatively high biomass production and carbon storage but low grain yield.
“These findings have opened new avenues for further research, like doing crosses to integrate these traits into a single genetic background, thereby creating a new population characterised by high carbon storage, substantial biomass production, and high grain yield,” said Ngidi.
“Some of the high-performing sorghum genotypes identified in my research have the potential for commercialisation. This could lead to the development of improved sorghum varieties that are more productive and environmentally sustainable, benefiting both farmers and the broader agricultural industry”, said Ngidi. He is currently completing the write-up of his thesis and looking forward to plunging into his PhD research.
Read: Ngidi, A., Shimelis, H., Abady, S., Figlan, S., & Chaplot, V. Response of Sorghum bicolor genotypes for yield and yield components and organic carbon storage in the shoot and root systems. Sci Rep. 14, 9499 (2024). https://doi.org/10.1038/s41598-024-59956-x
Words: Shelagh McLoughlin
Photo: Supplied