A wheat breeder at a trial field at the National Agricultural Crops Resources Research Institute explains the breeding process to journalists PHOTO/LOMINDA AFEDRARU
Heat and drought stress are forming two of the main environmental constraints on wheat production in Sub-Saharan Africa.
In some African countries, temperatures often exceed 41 degrees Celsius and this severely undermines the flowering and grain-filling stages of wheat, leading to low yields averaging 2 tonnes per hectare against the expected 6 tonnes per hectare.
The increasing occurrence of extreme heat and drought spells due to climate change is making this situation even worse.
Due to the warm climate patterns in Africa, the International Centre for Agriculture Research in the Dry Areas (ICARDA), in partnership with National Agricultural Research Systems has developed a series of heat-tolerant wheat varieties which have been successfully released across countries in the Sahelian zone.
These improved lines of wheat are able to withstand temperatures that are 4 degrees Celsius higher than normal, which offers real advantage for production zones subject to heat at critical times during the growing season.
Higher and more stable yields over successive growing seasons are achieved by farmers who cultivate heat-tolerant wheat varieties, reaping up to 6 tonnes per hectare.
As such scientists at the National Crops Resources Research Institute (NaCRRI) in Namulonge have adopted some of the drought tolerant wheat varieties which is being bred at the institute for farmer adoption.
Background
Wheat farming in Uganda began in 1912 when bread wheat was first grown on the slopes of mountain Rwenzori.
It is now a vital part of Uganda's food system, especially in the bakery industry. However, Uganda imports most of its wheat to meet domestic demand.
Since its introduction, wheat has traditionally been grown above in areas 1500m above sea level, mainly on the slopes of Mt Elgon, Mt Rwenzori and Mt Muhavura.
Presently, wheat is mainly produced in the districts of Kapchorwa, Kabale, Kisoro, Kaborole, Kasese, Buhweju, Isingiro and Zombo.
However, production in these areas is very low and, in some instances, lacking altogether.
According records by Food and Agriculture Organisation, the total area under production in 2018 was estimated at 14,504 hectares, with a corresponding annual production of 23,206 metric tonnes.
Domestic consumption of wheat stands at an average of 631,634 metric tonnes by 2018 and local production only provides about 4 percent of this demand.
According to the United Nations COMTRADE database on international trade, Uganda wheat and meslin a mixture of grasses and legumes used for animal feed imports from Russia in 2018 alone was $91.35 million.
Though traditionally wheat is not the leading staple crop in sub-Saharan Africa and Uganda in particular, it is increasingly becoming an important food crop because of rapid population growth associated with increased urbanisation and change in food preference such as bread, biscuits, pasta, noodles and porridge.
This implies that a concerted effort must be made to increase local production to meet demand and avoid over-dependence on imports.
This would go a long way in saving foreign exchange through import substitutions.
Smallholder farmers would also benefit from wheat production, which would increase their earnings Ugandan scientists are currently conducting research in dryland areas to foster wheat farming.
Wheat farming in Uganda Mr Daniel Bomet Kwemoi a wheat breeder at NaCRRI explained that wheat grows in cool areas across the globe, the reason why in Uganda it is grown in highlands.
Most farmers growing the crop obtain seed from Kenya and the most common variety is called Fahari.
There are also improved varieties which were released by Naro,namely Naro I, II and III. These varieties are resistant to yellow rust, leaf rust and UG99 disease.
They are also high yielding, with a yield rate of 2.5–3 tonnes per hectare.
These varieties are grown in cool areas. It is a requirement that farmers plant 40kg to 50kg seed per hectare.
The dryland wheat breeding Bomet explained that he is teaming up with wheat breeder Bosco Chemayek by conducting the research at NaCRRI and Buginyanya Zonal Agricultural Research and Development Institute (BugZardi) in eastern Uganda. The scientists contend that the breeding for heat-stress tolerance in wheat varieties is achieved through conventional methods, including multi-location screening, shuttle breeding, double haploids, marker -assisted selection and key location phenotyping.
The key mechanisms against heat and drought stress of improved lines are super-early maturing traits because they mature within 90 days.
Seed multiplication of heat and drought-tolerant wheat varieties in Sub-Saharan Africa, like elsewhere in the world, is done by private companies, and commercial and small scale farmers themselves.
The process is the same as for other cultivar, and involves 3-4 growing cycles starting from breeder seed which is provided by national and international agricultural research centres.
In a first step, basic seed is produced that gets carefully inspected for deviances for ensuring true-to type seed passes on.
The basic seed is then planted again to produce certified seeds for distribution and sales.
Bomet and his team obtained drought-tolerant seed from the International Centre for Improvement of Maize and Wheat (CIMMYT) and International Centre for Agricultural Research in the Dry Areas (ICARDA).
This is under project funded by the International Development
Research Centre (IDRC) of Canada, within the auspices of the Science Granting Councils Initiative (SGCI).
They have since evaluated and tested different improved varieties in Uganda’s six wheat ecological areas.
For the mid-highlands evaluations were done in Bukwo and Kween in eastern Uganda,Rwebitaba in western Uganda, Bulengeru.
Here the productivity is 2 tonnes per hectare.
For the lowlands, it was in Ngenga, Ikulwe in the Karamoja region, Namulonge, Masindi and Kasese.
Here the productivity is 1.8 tonnes per hectare.
After doing the selections, the team has also come up with two candidate varieties that grows well both in highland and non-highland parts of Uganda.
The team is optimistic that the research process is nearing completion and they hope to release the varieties this year.
Other research initiatives
According to information from ICARDA it is stated that since 2013, more than 30 climate resilient wheat varieties that combine high yield potential and heat and drought-tolerance have been released by ICARDA across countries in Sub-Saharan Africa.
This collection of lines is characterised by an early harvest maturity of 90-100 days, morphological and physiological protection mechanisms against extreme temperature and low rainfall and good bread-making quality.
This requires 14-15 percent protein content, resistance to stem rust diseases like Ug99 that are common across the continent.
Eastern and Southern Africa is possessed by a series of heat and drought-tolerant varieties that were developed through conventional breeding or genetic modification.
Already countries which include Burkina Faso, Eritrea, Ethiopia, Kenya, Malawi, Mali, Niger, Nigeria, Senegal, Sudan, Zambia have commercialised the drought-tolerant wheat varieties and Uganda will soon follow suit.
What takes for farmers to adopt these varieties
The scientists contend that rapid and widespread uptake of newly developed heat and drought-tolerant wheat varieties requires identifying high yielding lines with stress resistance that are adapted to local growing conditions and fulfil preferences of farmers and markets.
It is important to provide breeder seed and capacity building to private companies and It is also important to enhance stable agricultural and trade policy frameworks that make wheat production cost-effective and attractive for farmers and reinforcing information, marketing, transportation and value-add infrastructures within growing areas that improve linkages among farmers, processors and consumers.
