By Naftali MUNGAI

JULY 5, 2005 marked a watershed in the growing of maize in sub-Saharan Africa. On the relatively cool and shiny day in the Lake shore town of Kisumu in western Kenya, more than 70 delegates from 16 African countries gathered for the launch of the imazapyr-resistant (IR) maize, also known as the clearfield technology.
The IR maize has been bred for resistance to imazapyr, a herbicide that is routinely used to kill weeds on maize farms in countries such as the United States.
Imazapyr is one of a class of herbicides known as imidazolinones, and the IR maize is derived from a natural mutation that offers resistance to this herbicide. This means that it is not a genetically modified crop, as some people are wont to misinterpret.
Though IR maize became commercially available in the US as early as 1993, but it has taken more than 10 years to become available in Kenya, according to Dr Jonathan Gressel of the Weizmann Institute of Research in Israel.
The institute, in partnership with the International Centre for Maize and Wheat Improvement (Cimmyt), the Kenya Agricultural Research Institute (KARI), the African Agricultural Technology Foundation (AATF), the Rockefeller Foundation and the BASF chemical company, are the institutions behind the new maize type, whose main attribute is the control of one of the most noxious weeds in the world --- the witch-weed or the striga.
The striga, which is popularly known as kayongo among the Luo and oluyongo among the Luhya, both western Kenya communities, is a parasitic weed that thrives only in the presence of cereals such as maize and sorghum.
Dr Fred Kanampiu of Cimmyt says that the striga’s distribution has continued to increase in the face of decreasing soil fertility, coupled with intensified cereal cultivation. “Striga is a parasitic weed that only germinates in the presence of cereals such as maize, sorghum, millet and rice,” he told participants at the Kisumu conference.
“Wherever it occurs, striga is the bane of maize farmers. It thrives in poor soils that are deficient in nutrients, as are found in western Kenya.
“The striga attaches its roots to the cereal plant, sucking in nutrients and water and also releasing phytotoxins, which adversely affect these plants.”
A single plant is capable of producing between 50,000 and 200,000 dustlike seeds, which may lie dormant in the soil for as long as 20 years until a suitable host plant is found. The official launch of the IR maize was conducted by the Kari director, Dr Romano Kiome, who is also a member of the Cimmyt board of trustees.
Dr Kiome gave a detailed account of the importance of maize in Kenya and other sub-Saharan African countries. “Consumption of maize in Kenya stands at 100kg per person per year, and even when maize deficit goes up by 1-2 per cent, the president declares an emergency,” he said. “In fact, when we talk about famine in Africa, we refer to a maize deficit.”
And to emphasise the gravity of the striga problem, Dr Kiome said that in April, this year, Kenya’s President Mwai Kibaki himself contacted the institute seeking to know what could be done about the menace.
The director of the African Livelihoods Programme at Cimmyt, Dr Marianne Banziger, told the participants that the programme would make sure that the IR maize is made available to all countries in sub-Saharan Africa.
“We are aiming at a rapid variety release that will make the IR maize available in these countries in two to three years,” said Dr Banziger, adding that much of the best maize germplasm had been converted to IR.
Peter Matlon of the Rockefeller Foundation said the organisation sees a major role of the IR maize in food security in Africa, hence the support given to the technology over the last nine years.
“The major challenge has been the ‘commercial proof-of-concept’ in Kenya which will then be extended to other African countries,” he said.
Prof. Wilfred Mwangi of Cimmyt, a former permanent secretary (chief accounting officer) in the ministry of agriculture in Kenya, urged African countries to live up to their pledge of allocating 10 per cent of their budgets to agriculture, saying that it continues to be a major player in the African economies.
From as early as 1936, the striga, with its beautiful purple flower, was described as a serious problem in western Kenya as well as in numerous other countries in sub-Saharan Africa. Researchers started working on its control as early as 1940, but it is in the last 20 years that the efforts were intensified.
Today, it is estimated that 20 million hectares of maize in sub-Saharan Africa are affected by the two species, Striga hermonthica, which is prevalent in West Africa, and Striga asiatica, which is common in the Kenyan coast.
Maize yield losses from the striga are estimated at between 30 per cent and 100 per cent, or a whopping US$1 billion. Coupled with this is the ensuing deforestation as communities desert their farmlands and invade forests in search of virgin land devoid of the noxious weed.
In Kenya alone, the weed has invaded approximately 200,000 hectares of farmland, resulting in losses of about KShs800 million (about$10 million) each year. And the weed continues in its relentless march, infesting new maize fields each year.
Over the years, farmers have practised several control methods, but these have been wanting in sustainability. Among them are cultural control methods such as crop rotation and the plants’ uprooting and burning. However, the efforts have been thwarted by the seeds’ long period of dormancy in the soil.
In the US, the weed is controlled by applying large doses of ethylene, which makes the seeds burn themselves out through accelerated germination. This is a very expensive process and out of the reach of African farmers.
But now, with the advent of the IR maize that is complemented by coating the seeds with imazapyr, this intractable weed is soon being reined in. The control method combines low-dose seed coating strigaway (imazapyr) and imazapyr-resistant maize, which a dual-approach control method.
Dubbed Ua Kayongo (Swahili for kill the striga), it is a cheap but very effective method. The imazapyr coating ensures that a plant that penetrates the maize plant is killed by the herbicide because it is systemic, while the maize which is resistant to the herbicide survives. The maize seeds are also coated with lindane, an insecticide, and fungicide thiram to protect them until they germinate.
Demonstrations by Cimmyt and Kari have shown that by using strigaway, maize fields remain striga-free for almost the entire season and that even in heavily infested area, maize production can be increased three-fold or more, for an investment that costs about Shs 300 per hectare. Experimental results show that by treating IR maize seeds with 30 grammes of imazapyr, maize yield increases from 930 kilogrammes in an untreated field to 3063 kilogrammes in the treated field.
In terms of profit to the farmer, it works out that even with 10 per cent loss from striga, the farmer could benefit by Shs4,700 per hectare, and when one considers that losses could be in excess of 50 per cent, the benefit to the farmer is even greater.
“Such a farmer will be moving from poverty to income generation; from subsistence to wealth and from food insecurity to food security,” said the Kari director.
However, because of the fear that farmers may not deploy the technology in the correct manner, either by under-dosing the seeds or other malpractices, the technology will be available only to seed companies, at least in the short run.
Said Dr Kanampiu: “The key people to be trained are the seed companies so that the technology can be sustainable. But this has its shortcomings in that the farmers will have to purchase seeds every year from the seed companies.”
Most farmers interviewed expressed their enthusiasm and satisfaction with the IR seeds. However, they expressed the desire to be allowed access to the technology so that they may harvest their own seeds and treat them.
One of them, Onyango Baridi, told BN: “We are very anxious to get this seed into our farms but the cost is still a constraint for us. We would be happier if we could be allowed to harvest our own seeds and treat them.”
But Dr Kanampiu and the other stakeholders fear that if this is allowed, not only will yields gradually decline, but that such practices may also lead to the striga becoming resistant to the Strigaway.
“We must prevent the chances of African maize growers selecting for herbicide resistance by the striga itself by putting in place certain stewardship practices,” he says.
However, the stakeholders are confident that the majority of farmers will be able to afford the extra KShs300 per hectare and with 60 per cent of farmers in Nyanza and Western Kenya already buying hybrid maize seeds, this confidence is not misplaced.
“Lagrotech, Western Seed Company and Kenya Seed Company will be marketing the I-R maize seed and this will be available in the next short rains that are expected in September/October,” said Dr Kanampiu.
The other fear expressed by farmers is whether intercropping IR maize with legumes such as beans and cowpeas will affect the legumes. However, Dr Kanampiu said that their trials had shown that as long as the nearest bean plant is at least 15 centimetres away from the treated maize, there was no adverse effect, meaning that the technology is compatible with traditional small-scale farmers’ intercropping technology.
These measures, says Dr Kanampiu, will see most farmers in western Kenya making some headway in alleviating the grinding poverty that has taken root in these communities and move them towards income generation and food self-sufficiency.