Resistant varieties are new crop varieties that improve yield production, are resistant to pests and diseases, more tolerant to drought, salinity or other changing or undesirable environmental conditions. Crop plants used within this practice are usually only resistant to a limited number of undesirable characteristics e.g. pests or drought – but usually not both, and some other desirable traits may be lost while others may be strengthened. Hence, careful selection of candidate species must be undertaken. Resistance varieties common in southern Africa include drought resistant maize, sorghum, rice and cowpea (beneficial legume for intercropping) strains, striga (witch weed) resistant sorghum and maize strains, and others all help farmers adapt to changing climate conditions, by being able to farm crops that survive the increasingly variable climate, which can result in less rainfall, or the presence of new pests. Striga results in crop losses totalling over USD 1 billion per year, whereas research has shown that planting climate resilient maize varieties can lead to up to a 25 % increase in crop yields.
Exploring new pest or drought resistant varieties in a regional will require demonstration and testing in ‘test plots’, so extension workers can ensure that the outcomes are aligned with farmers wants/needs/tastes, and so farmers are familiar with the new varieties before they are mainstreamed. Acceptance of new varieties, and any changes is traits will be critical, as resistant varieties is a key intervention for climate adaptation in southern Africa, as they will allow farmers to remain productive for longer under challenging conditions, and while different crops altogether are investigated.
To effectively leverage resistant varieties, the following should be carried out:
- Step 1: Survey farmers and meet with other local and national level extension officers to determine key interventions required – drought tolerance, prevalence of certain pests, etc.
- Step 2: Research and meet other local extension officers to discuss best methods applied to the agricultural practice of resistant varieties in the region.
- Step 3: Talk to the agricultural dealers and seed manufacturers about the varieties being offered and their characteristics.
- Step 4: Talk to the agricultural research departments about best opportunities under climatic change in your specific area.
- Step 5: Either independently or in partnership with seed manufacturers, establish test plots of viable resistant varieties in key locations to act as demonstration plots for farmers to visit, observe growth and harvest, and test the outcomes. Many conditions may come into play when attempting to mainstream resistant varieties, including visual aspects, harvesting and processing differences, palatability and taste, etc. All of these issues must be discussed with farmers during testing and roll-out to ensure resources are not wasted with varieties that will fail.
- CIMMYT, 2017. New crop varieties that counter climate change: a best bet for farmers.
- The Food and Agriculture Organisation of the United Nations (FAO), 2005. Status of Research and Application of Crop Biotechnologies in Developing Countries. Rome, Italy.
- CIMMYT 2015. Maize Variety Options for Africa: Angola. International Mazie and Wheat Improvement Centre. Nairobi, Kenya.
- DTMA 2015. Drought Tolerant Maize: A quarterly bulletin of the Drought Tolerant Maize for Africa Project. Nairobi, Kenya.
- DTMA 2015. Drought Tolerant Maize for Africa Project. Nairobi Kenya.
- ReliefWeb 2019. Becoming Drought Resilient: Why African Farmers Must Consider Drought Tolerant Crops. ReliefWeb website.
- AATF 2006. Empowering African farmers to eradicate Striga from maize croplands. The African Agricultural Technology Foundation. Nairobi, Kenya.
- Cairns, J.E. and Prasanna, B.M. 2018. Developing and deploying climate-resilient maize varieties in the developing world. Current Opinion in Plant Biology, 45: 226-230
Benefits
- The practice is widely used to increase yield production, produce pest and disease resistant varieties and improve environmental tolerance.
- Further combines the best traits of the parental forms resulting in some strengths and weaknesses, resulting in a variation of crops species.
Drawbacks
- May require investment and/or access to credit, as new seeds will not be in farmer seed banks/stores and may be expensive to kick-start implementation.
- May take time to launch new varieties and gain acceptance from farmers/consumers/markets.
