The Kenya Plant Health Inspectorate Service (KEPHIS) has approved three new maize varieties that are resistant to the deadly necrosis disease
The Tumaini 1 variety, also known as Type Wei 101, will soon be released to Kenyan farmers and has been deemed suitable to farmers in Bomet, Nakuru and Narok counties as well as areas in the lower eastern part of the East African country.
KEPHIS has bred the new variety in collaboration with the Kenya Agricultural Research Institute (KARI), the Global Maize Programme of the International Maize and Wheat Improvement Centres (CIMMYT) and the Africa Agricultural and Technology Foundation (AATF).
Three other highly tolerant varieties – Wei 108 and WM 1259 both from KARI and MZ 1202 from the Kenya Seed Company (KSC) – have also been undergoing further testing.
"Tests are at advanced stage," said KEPHIS managing director Dr James Onsando. "We are fast-tracking the process and the varieties could be released before the end of the year."
Maize necrosis was first noticed in Bomet County in 2011 and has ravaged more than 75,000 hectares in the Rift Valley. Symptoms of the disease include the withering of young leaves from the leaf margins to the mid-ribs. Severely affected plants have small cobs with little or no grains setting. Plants frequently die before tasseling, according to an initial disease report produced by KARI.
Field observations have indicated a 30-100 per cent loss of the crop depending on the stage of the maize when first affected. Researchers across Kenya have been using breeding techniques to come up with varieties tolerant or resistant to the necrosis disease.
"Use of hybrid varieties, which show some level of resistance to the virus, is the most successful way of managing the disease," observed Dr Anne Wangui, a virologist with KARI. "Farmers are also being encouraged to grow alternative crops in order to break the virus transmission cycle."
According to Dr Wangui, the most suitable alternative crops include potatoes, cassava, cabbage, carrots and sweet potatoes.
Agricultural experts have also warned that mixing several varieties of maize on one farm and failure to practice intercropping and crop rotation may be exacerbating the problem. For example, experts have noted that intercropping sweet pepper or onion with maize, kales or beans could reduce the impact of the maize virus.
KARI scientists have already found that the maize necrosis disease is caused by a combination of two diseases.
"The Sugarcane Mosaic Virus and Maize Chlorotic Virus have been identified through molecular techniques with the later accounting for over 60 per cent of yield loss," asserted Dr Wangui.