IR maize: Imazapyr resistant maize for Striga management

Boost maize yields while eliminating the issue of Striga infestation

The "Imazapyr resistant maize for Striga management (IR maize)" technology is a maize variety that has been genetically modified to exhibit resistance to imazapyr, an herbicide effective in protecting maize crops from parasitic Striga weeds. These improved maize lines, known as IR maize, have been specifically designed for regions in Sub-Saharan Africa heavily affected by Striga, a parasitic weed that significantly impacts crop productivity by sapping nutrients and water from maize plants. IR maize not only safeguards against Striga but also reduces the growth and negative impact of other common weed types, contributing to improved grain and stover productivity, as well as nutrient and water use efficiency in maize crops. This technology has led to substantial enhancements in food self-sufficiency and economic returns in maize farming across Sub-Saharan Africa.

This technology is TAAT1 validated.

7•7

Scaling readiness: idea maturity 7/9; level of use 7/9

Project adoption4

Technology integrated in the EFPP- Guinea, ENSURE- East Africa, PADCV-PTA- Democratic Republic of the Congo, and PUPSAN- Mali projects.

Project	Beneficiaries	Budget	Duration	Key figures
EFPP- Guinea Guinea Emergency Food Production Programme	35,750 farmers (at least 30% of whom are women). 1,650 livestock farms.	25.23 million	2022–2024	2,000 tons of rice seeds and 750 metric tons of corn. 4,845 tons of NPK fertilizer.
ENSURE- East Africa Enabling Environments for Sustainable Regional Agriculture Extension	3,000,000 farmers.	13.14 million	2024–2027	149,940 farmer leaders & trained farmers. 9,996 trained. 2 → 3.5 t/ha.
PADCV-PTA- Democratic Republic of the Congo Projet d’Appui au Developpement des Chaines de Valeurs en soutien au Programme de Transformation de l’Agriculture	900,000 smallholder farmers (including 450,000 women).	321 million	2024–2029	62,000 tons of certified seeds. 30,000 people trained. 5,200 hectares of irrigated rice cultivation.
PUPSAN- Mali Emergency Production and Food & Nutrition Security Project	35,274 vulnerable farmers (31.5% women and 20% young people).	7.04 million	2023–2026	1,027.14 tons of certified seed. 2,234 tons of fertilizer.

See project details ›

Adults 18 and over: Positive high

The poor: Positive medium

Under 18: Positive low

Women: Positive low

Climate adaptability: Highly adaptable

Farmer climate change readiness: Significant improvement

Biodiversity: Positive impact on biodiversity

Carbon footprint: Same amount of carbon released

Environmental health: Greatly improves environmental health

Soil quality: Improves soil health and fertility

Water use: Same amount of water used

Problem

Severe Striga weed infestations in maize crops, particularly in Sub-Saharan Africa, leading to significant yield losses.
Reduced grain yields and crop productivity due to the parasitic nature of Striga, which competes with maize for nutrients and water.
Limited food self-sufficiency and economic returns in maize farming areas affected by Striga infestations.
Herbicide reliance and the need for effective Striga control methods.

Solution

Development and marketing of improved maize varieties that are genetically modified to be resistant to imazapyr, a herbicide effective in protecting maize crops against Striga weeds.
Introduction of IR maize lines in areas severely affected by Striga, enhancing grain yields and curbing the further spread of the weed when combined with appropriate soil and fertilizer management.
Use of IR maize seeds coated with imazapyr instead of non-resistant hybrid varieties, leading to increased grain and stover productivity and improved nutrient and water use efficiency.
Reduction in herbicide usage for Striga control by precisely delivering the imazapyr agent through seed dressing, effectively inhibiting Striga spore germination near maize roots during the critical stages of crop establishment.
Genetic engineering of maize germplasm to incorporate an 'IR' gene, making maize plants resistant to imazapyr herbicides.
Marketing of maize varieties combining imazapyr resistance with other valuable traits, such as drought tolerance and biofortification.
Season-long protection against Striga on fields, even in areas with varying Striga seedbanks and levels of parasitism of untreated maize varieties.
Compatibility of IR maize with degraded fields and low soil fertility when combined with the appropriate supply of inorganic fertilizers and organic resources.
Use of the non-toxic herbicide imazapyr, which is applied in micro-doses through IR technology.
Coating of herbicides onto maize seeds using a binding agent like Arabic gum, ensuring stable application and effectiveness.

Key points to design your program

IR maize technologies help farmers control Striga hermonthica, one of the most destructive parasitic weeds affecting maize production in Sub-Saharan Africa. By using herbicide-coated resistant seed, the technology protects maize during the critical early stages of crop establishment, reducing Striga infestation while improving grain productivity, nutrient- and water-use efficiency, and farm profitability. It is well suited for food security, sustainable crop intensification, and agricultural productivity programmes, contributing to SDGs 2 (Zero Hunger) and 8 (Decent Work and Economic Growth). The technology also promotes the inclusion of women, youth, and vulnerable rural households through improved access to quality seed and extension services. To successfully integrate this technology, consider the following key actions:

Identify priority maize-growing areas where Striga hermonthica significantly constrains productivity, food security, and farmer incomes.
Establish partnerships with IITA, AATF, national research institutions, seed companies, extension services, farmer organizations, and national seed authorities to strengthen technology deployment and certified seed systems.
Strengthen seed systems by supporting the multiplication, certification, herbicide coating, and distribution of quality IR maize seed while promoting improved varieties adapted to local production conditions.
Promote integrated Striga management by combining IR maize with appropriate fertilizer management, improved soil fertility practices, and crop rotations or intercropping with legumes to achieve sustainable control.
Train extension agents, seed producers, agro-dealers, and farmers on the safe handling and proper use of herbicide-coated seed, integrated Striga management, and recommended agronomic practices.
Strengthen extension services through demonstration plots, farmer field schools, and digital advisory platforms to accelerate technology adoption.
Promote equitable access for women, youth, and vulnerable rural households through targeted seed distribution, technical training, and extension support.
Monitor programme performance through indicators such as certified seed distribution, technology adoption, Striga incidence, maize productivity, farmer income, and the participation of women and youth.

IP

Open source / open access

Scaling Readiness describes how complete a technology\’s development is and its ability to be scaled. It produces a score that measures a technology\’s readiness along two axes: the level of maturity of the idea itself, and the level to which the technology has been used so far.

Each axis goes from 0 to 9 where 9 is the “ready-to-scale” status. For each technology profile in the e-catalogs we have documented the scaling readiness status from evidence given by the technology providers. The e-catalogs only showcase technologies for which the scaling readiness score is at least 8 for maturity of the idea and 7 for the level of use.

The graph below represents visually the scaling readiness status for this technology, you can see the label of each level by hovering your mouse cursor on the number.

Scaling readiness score of this technology

Maturity of the idea 7 out of 9

Semi-controlled environment: prototype

Level of use 7 out of 9

Common use by projects NOT connected to technology provider

Maturity of the idea										Level of use
9
8
7
6
5
4
3
2
1
	1	2	3	4	5	6	7	8	9

Project	Beneficiaries	Budget	Duration	Key figures
EFPP- Guinea Guinea Emergency Food Production Programme	35,750 farmers (at least 30% of whom are women). 1,650 livestock farms.	25.23 million	2022–2024	2,000 tons of rice seeds and 750 metric tons of corn. 4,845 tons of NPK fertilizer.
ENSURE- East Africa Enabling Environments for Sustainable Regional Agriculture Extension	3,000,000 farmers.	13.14 million	2024–2027	149,940 farmer leaders & trained farmers. 9,996 trained. 2 → 3.5 t/ha.
PADCV-PTA- Democratic Republic of the Congo Projet d’Appui au Developpement des Chaines de Valeurs en soutien au Programme de Transformation de l’Agriculture	900,000 smallholder farmers (including 450,000 women).	321 million	2024–2029	62,000 tons of certified seeds. 30,000 people trained. 5,200 hectares of irrigated rice cultivation.
PUPSAN- Mali Emergency Production and Food & Nutrition Security Project	35,274 vulnerable farmers (31.5% women and 20% young people).	7.04 million	2023–2026	1,027.14 tons of certified seed. 2,234 tons of fertilizer.

Countries with a green colour: Tested & adopted
Countries with a bright green colour: Adopted
Countries with a yellow colour: Tested
Countries with a blue colour: Testing ongoing

Countries where the technology is being tested or has been tested and adopted
Country	Testing ongoing	Tested	Adopted
Ethiopia	–No ongoing testing	Tested	Adopted
Kenya	–No ongoing testing	Tested	Adopted
Malawi	–No ongoing testing	Tested	Adopted
Mozambique	–No ongoing testing	Tested	Adopted
Tanzania	–No ongoing testing	Tested	Adopted
Uganda	–No ongoing testing	Tested	Adopted
Zambia	–No ongoing testing	Tested	Adopted
Zimbabwe	–No ongoing testing	Tested	Adopted

This technology can be used in the colored agro-ecological zones. Any zones shown in white are not suitable for this technology.

Agro-ecological zones where this technology can be used
AEZ	Subtropic - warm	Subtropic - cool	Tropic - warm	Tropic - cool
Arid
Semiarid
Subhumid
Humid

Source: HarvestChoice/IFPRI 2009

The United Nations Sustainable Development Goals that are applicable to this technology.

Goal 2: zero hunger

Goal 8: decent work and economic growth

1. Seed Selection and Preparation:

Obtain high-quality IR maize seeds from a reliable source. Use gloves when handling the coated IR maize seeds to avoid exposure to the herbicide.

2. Soil and Fertilizer Management:

Follow the best soil and fertilizer management practices recommended for your specific growing area and conditions.
Ensure that the soil surface is well-tamped down to help the herbicide reach the surrounding soil.

3. Planting IR Maize:

Plant IR maize seeds as you would with any normal maize crop.
Ensure proper seed spacing and planting depth according to local recommendations.

4. Fertilizer Application:

Apply inorganic fertilizers, with a particular emphasis on nitrogen, as these have been shown to increase yields from IR maize and reduce Striga infestation.
Fertilizer application addresses soil limitations and helps the crop grow stronger.

5. Intercropping or Rotation (if needed):

On farmlands with high rates of Striga infestation, consider intercropping or rotating with food legumes like soybean or cowpea, or forage legume like greenleaf clover.
These additional crops can help manage Striga while diversifying agricultural output.

Last updated on Jul 3, 2026