Plant Mutation Breeding Enhance Crop Productivity and Food Security in Drought-Prone Environments in Namibia

The IAEA technical cooperation project NAM/5/009: “Using Mutation Breeding and Integrated Soil Plant Management Techniques to Develop Sustainable, High Yielding and Drought Resistant Crops of Pearl Millet, Sorghum and Cowpea” was set up in 2009 as a collaboration between the Government of the Republic of Namibia through the Ministry of Agriculture, Water and Forestry and the International Atomic Energy Agency (IAEA), with the support of the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture.

The objective of the project was to apply plant mutation breeding and soil management techniques to develop new mutant lines/varieties with high yield potential and enhanced tolerance to drought conditions for drought affected farms. Seeds of local varieties of cowpea, sorghum and pearl millet were treated with gamma rays at the FAO/IAEA’s Laboratories, Seibersdorf, Austria.

The treated seeds were shipped back to Namibia and planted, and a mutation breeding programme was initiated by the Ministry of Agriculture, Water and Forestry. Three crop research stations have been involved in developing new improved mutant varieties: Omahenene in the North West, Mannheim in the North Central and Bagani Research in the North East of Namibia. The R&D effort in Namibia was supported by the Joint FAO/IAEA Centre in 2009 in the form of a fellowship training programme in plant mutation breeding at the FAO/IAEA Laboratories, Seibersdorf, Austria.

In subsequent years, several young scientists (eight in plant breeding and eight in soil and water management) have been trained in nuclear techniques applied in plant mutation breeding and soil and water management. The training targeted techniques that produce desired mutants and those that could be used in developing and advancing selected mutant lines for field performance trials in Namibia for drought tolerance in cowpea, sorghum and pearl millet.

One major achievement has been the development of a semi-coiled ( in figure 3 left) - straight pod cowpea (( in figure 3 right ) mutant of the local variety Shindimba (Figure 3). Most farmers prefer a straight pod to the highly coiled pods of Shindimba, and farmers are now happy with to have an improved semi-coiled - straight pod “Shindimba” mutant.

Early maturing (a drought avoidance trait), drought tolerant and better yielding mutant cowpea lines have been developed and introduced to farmers during the 2015/16 season for performance testing in farmers’ fields.

These mutants are well adapted and performed well under local farm management conditions. The local farmers themselves demonstrated that the advanced mutant lines performed better than local varieties without supplementary irrigation under severe water stress.

Drought tolerant mutant lines will enable farmers to protect their harvest, minimizing losses during severe drought and helping them to cope with the consequences of climate change.

The common seed colour of cowpea is white; however variation in seed colour was produced and developed as farmers have different preferences for seed colour and most would like to plant all the seed colour types when they become available (Figures 5, and 6?).

Improved mutant lines, with different seed colour, will enable farmers to grow and harvest consumer-preferred cowpea varieties that will increase their income.

Advanced field experiments are continuing in multi-location trials in Namibia for yield, drought, temperature stress and pest and disease evaluations.

Pre-variety release field day events are planned to show off highly productive mutant varieties for drought prone areas in the coming years and seed stocks are being bulked to provide enough planting materials for distribution to farmers in 2018.