Understanding mutation breeding for drought tolerance in crops
Mutation breeding is an effective technique to increase resilience to drought in crops grown in drought-prone countries. At a recent training course held in Namibia, crop improvement scientists learned about the principles and practical aspects of using mutation breeding to improve drought tolerance traits in crops such as sorghum, cowpea and pearl millet, among others. The training course, ‘Improving resilience to drought through mutation breeding’, attracted participants from 15 African countries that are actively involved in research concerning mutation breeding in various crops.
Drought is one of the major constraints to high crop yields in Africa. Researchers across the globe need to share germplasm, mutants and protocols for mutation breeding to impart drought tolerance in crops.
Dr Ashok Kumar, Principal Scientist, Sorghum Breeding, ICRISAT, was invited by the International Atomic Energy Agency (IAEA), Vienna, Austria, to guide the training course, along with Prof H Shimelis from the University of KwaZulu-Natal (UKZN), Republic of South Africa. Dr Kumar was responsible for explaining the theories via lectures and hands-on sessions in the field on various topics, some of which were as follows:
Introduction to mutation induction for crop improvement
- Mutagen concepts, sources and radio sensitivity
- Crop genetic enhancement for climate change adaptation
- Genetic basis and drought resistance
- Breeding procedures, handling of mutated populations
- Identification, evaluation and selection of developed varieties/breeding lines till release process
- Use of genomics for improving drought resistance
- Physiology of abiotic stresses, especially drought tolerance
- Progress in sorghum improvement research
- Applications of generation advancement techniques in mutation breeding programs (double haploid, embryo culture)
- Screening methodologies for drought stress tolerance
- Basic statistical analysis for breeding programs
Apart from the training sessions, the researchers visited the Mannheim Research Station of the Namibian Ministry of Agriculture, Water and Forestry (MAWF) near Tsumeb, Namibia, to see advanced stage (M8) mutant lines evaluation trials of cowpea, sorghum and pearl millet.
The cowpea mutants were found very promising for grain yield, pod length, pod shape, grain color, early maturity and higher biomass production. In sorghum, the mutants showed larger panicles, higher grain number and larger grain size compared to the original parents (Macia and local red sorghum). It is interesting to note that Macia, the popular sorghum variety in Africa, was developed by ICRISAT and is now also used in mutation breeding research to isolate new mutants for traits of interest. In pearl millet, landrace cultivars were used for mutagenesis and the head size of mutant lines was bigger compared to the parents. The participants could identify promising mutants based on the mutants’ superiority compared to their parents. They recommended the release of promising cowpea, sorghum and pearl millet mutants to farmers for cultivation.
To encourage productive discussions, the training participants were divided into three groups, based on their preferences, to debate on self-pollinated, cross-pollinated and clonally propagated crops. Group members described their current research and shared their experiences with others. Each group was also asked to deliberate on and develop a draft proposal on ‘Mutation breeding for improving drought tolerance in a selected crop’ as a team.
In order to harness the genetic and natural resource management options among global researchers, the IAEA, together with the African Regional Cooperative Agreement for Research, Development and Training Related to Nuclear Science and Technology (AFRA), organized the training course which was hosted by MAWF. The idea behind it was to raise awareness about the need for global cooperation in research, and thus to improve the food security situation in Africa. The 15 training attendees included representatives of universities and research organizations of Benin, Burundi, Cameroon, Democratic Republic of Congo, Egypt, Ethiopia, Ghana and other countries. The course was conducted during 24-28 April in Tsumeb, Namibia.