Scientists put three deadly wheat diseases in focus

Dr Godwin Macharia a top wheat breeder at Karlo, Njoro. PHOTO | FRANCIS MUREITHI|NATION MEDIA GROUP

A group of scientists from across the world are meeting in Njoro, Nakuru County, to discuss how to eliminate three diseases that are a threat to the wheat crop, namely yellow rust, leaf rust and stem rust. Dr Godwin Macharia, a top breeder at Kalro and a wheat researcher, spoke to FRANCIS MUREITHI on the diseases and what farmers should expect from the meeting.

Why do the diseases remain a major challenge despite years of research?
These problems are historical since wheat was introduced in the country in 1900. A new race of stem rust, Ug99, was detected in Uganda and landed in Kenya in 2005. Some of our farmers are still growing old varieties that were developed in the 1970s and 1980s and are susceptible to these diseases. Besides, most smallholder farmers are not practising good agronomical practices in terms of using right fungicides because of the chemicals are expensive. These diseases tend to migrate to other regions due to different planting seasons, which makes it hard to eliminate them.
Crops such as barley are also host to the diseases and help them flourish producing more deadly races.

Your meeting discusses the two diseases, and others, what should farmers expect?

The meeting brings together global experts in wheat breeding, pathology and disease surveillance from more than 13 countries. We have trainees who will gain in-depth knowledge and ideas on how to combat these diseases and pass the knowledge to farmers. We shall also be able to share with our farmers on the new races of rusts as these deadly disease have no geographical boundaries. Our interactions will yield more resistance varieties that we shall develop in good time to benefit the farmers.

Are you working on new varieties that would be resistant to the diseases? If yes, when are they likely to come out?

We got to be ahead of the pathogens in this race to fight the diseases. Kenya Agricultural and Livestock Research Organisation (Karlo) is working closely with the Mexico-based International Maize and Wheat Improvement Centre (CIMMYT) and Kenya Plants Health Inspectorate Services (Kephis) on new varieties that have good yields and adopt well to different climatic conditions. The varieties would be high-yielding and they would be out hopefully by next September.

How can a first time wheat farmer identify these diseases and how does one curb them?

Yellow rust appears yellowish with powder like structures and it is easily rubbed off from the young leaves. The upper surface of the leaves appear like long dry stripes. It manifests in cold weather conditions. Stem rust appears later and attacks the stem. It is powdery like and leaves spores as it eats out the tissue of the plant leaving a reddish, elongated wound. The reddish wound turns black and the crop dries. Stem rust may also affect the leaves and the grain producing structure of the plant. Leaf rust is sporadic and manifests in powder looking structures that are orange in colour.  To curb them farmers should use resistance varieties, and stop relying on over-cultivated varieties. Regularly scout the diseases and spray fungicides at the right time.

Where are we globally in the fight against wheat rusts?
Researchers in wheat growing countries are collaborating with Food and Agricultural Organization (FAO), CIMMYT and through Borlaug Global Rust Initiative and expertise from Cornell University and funding from Bill and Melinda Gates Foundation to search for genes that would help develop resistant varieties that survives the virulent of rust diseases. Some of these materials are from India, China and Bangladesh and are being tested at Karlo, Njoro.

Kenya’s annual wheat production stands at 450,000 metric tonnes annually forcing the country to import to fill in the 60 per cent deficit. What are the wheat production constraints in Kenya besides diseases?
The Russian wheat aphid, which is devastating during dry spells, remains a big challenge. We further have African armyworms, rodents and birds, which damage the crop. Eroded soils and those which are low in organic matter due to overuse and those which are compact and have no space for water uptake and air to move freely also affect wheat farming. The rampant sub-division of arable land to pave way for construction of commercial projects is affecting production. Farmers’ inability to access to credit to support production is also a major problem. Cheap imports are hurting local farmers yet their production costs are high. Women wheat farmers face challenges as they have no access to land due to inheritance issues. Some fungicides used by farmers are inappropriately applied and affects production. New farmers are unable to buy fungicides as they are expensive.

What can Kenya do to boost wheat production?
Kenya should overhaul the whole wheat value chain and support the farmer to adopt appropriate technologies. The seeds system should be enhanced through Kephis to make sure farmers access quality planting material. Researchers should work closely with farmers to develop more resistance varieties. The farmers should also be sensitised on the need to embrace insurance package to boost their morale in case of a calamity that wipes their entire crop. Government should encourage formation of groups for farmers to easily access cheap insurance packages, promote use