Maize is at the center of global food security, as one of the most important cereal crops in human and animal diets worldwide. Together with rice and wheat, it provides at least 30% of the food calories to more than 4.5 billion people in 94 developing countries. This includes 900 million poor consumers for whom maize is the preferred staple.
Aside from providing nutrients for humans and animals, maize serves as a basic raw material for the production of starch, oil, alcoholic beverages, and biofuels. In the past decade, increasing demand and production shortfalls in global maize supplies have seen a surge in global maize prices. This problem has further been aggravated by climate change and the consequent rise in both crops biotic and abiotic stresses.
In the wake of these challenges, vigorous concerted efforts have been geared towards development of high-yielding, stress-tolerant maize varieties through conventional breeding and modern biotechnology.
Biotech or genetically modified maize has been engineered for protection against both biotic and abiotic stress including pests, herbicides, and drought. Herbicide-tolerant maize was first commercialized in 1996. To achieve this, a gene was incorporated in maize that confers tolerance to glyphosate herbicides such as Roundup® hence their name ‘Roundup Ready’ maize. Maize has also been engineered with the ability to tolerate glufosinate herbicides.
To protect from key insect pests, a bacteria Bacillus thuringiensis (Bt) gene has been engineered in maize. The protein product of the Bt gene targets lepidopteran insects like the maize stalk borer and the fall armyworm, therefore conferring resistance to these destructive pests. The proteins are highly selective, binding only to receptors in the target insect gut.
Recently, incorporation of more than one gene for crop improvement has led to the development of highly adaptable maize. This combination of traits is commonly referred to as stacked traits. Various combinations of stack traits including herbicide-tolerant/insect-resistant (HT/Bt) and insect resistant/drought tolerant (Bt/DT) have been achieved in biotech maize. The recently released eight-gene maize stack known by its trade name SmartStax™ is the result of crossing four different biotech maize lines to combine two herbicide tolerance genes with six Bt genes. The resulting stack features dual modes of control for weeds, lepidopteran, and coleopteran insect pests.
In 2017…
- Of the 188 million hectares (ha) maize area of global maize planted, 32% or 59.7 million hectares were biotech maize.
- 14 countries globally grew biotech maize in the year.
- The income benefit for farmers growing biotech maize during the 21 years (1996 to 2016) was US$63.7 billion and US$6.9 billion for 2016 alone.
In Africa, maize occupies approximately 24% of farmland, which is more than any other staple crop. However, production is continuously and severely affected by a number of threats, such as weeds, insect pests, viruses, fungi, low-quality seed, suboptimal post-harvest management, drought, and climate change. Given that Africa grows 90% of its maize under rain-fed conditions, drought has an enormous impact on yield. Erratic rain patterns, pests, inadequate farming methods, and drought stress can lead to 70-100% crop loss, which is dramatic for both farmers and consumers, as the whole food chain is affected.
To mitigate the pest and drought challenge, stacked biotech insect resistant/drought tolerant (Bt/DT) maize hybrids have been developed by the Water Efficient Maize for Africa (WEMA) project. It is projected that these hybrids will increase maize production by up to 2 to 5 million tons under moderate drought. In Kenya, two seasons of Confined Field Trials (CFTs) have produced promising results with the Bt/DT maize recording a significant yield advantage over the conventional counterpart under mild drought and stem borer infestation. Interestingly, the Bt trait seems to be controlling the fall armyworm, a current maize production menace in the country. The WEMA project coordinated by the African Agricultural Technology Foundation (AATF) started with five African countries including, South Africa, Kenya, Uganda, Mozambique, and Tanzania.
The succession of WEMA by TELA project in 2018 has seen Ethiopia added to this list. TELA project is aimed at providing farmers with climate-smart technologies that would enable them to mitigate the impacts of climate change.
In 2017, Mozambique planted the first field trial of biotech maize (insect-resistant and drought-tolerant) as part of the WEMA program. Tanzania also approved the same stacked trait, demonstrating a growing interest in the continent to incorporate more traits in various crops. South Africa, Kenya, and Uganda continued to conduct multi-location trials on biotech maize for insect resistance and drought tolerance. Nigerian and Swaziland governments issued import permits for biotech maize to meet food and feed deficits. Approval of nine biotech maize events was granted to WACOT Nigeria Limited for feed processing.
In Kenya, discussions are still on-going to initiate insect-resistant maize National Performance Trials (NPTs) following the conditional approval for general release granted for WEMA maize in 2016. This is particularly urgent for the country and the continent given significant levels of control of the devastating fall armyworm (FAW) have been observed in the insect-resistant maize experimental trials even though this particular trait is not for FAW control. Promising results with specific FAW control are already at advanced stages of research in South Africa.
The increase in income benefits for farmers growing biotech maize during the 21 years (1996 to 2016) stood at US$63.7 billion. Only one African country (South Africa) benefitted from these revenues at the time when over 300 million Africans who depend on maize as a staple were denied the choice to adopt biotech crops, suffering a huge opportunity cost.
Source:
GLOBAL STATUS AND ECONOMIC BENEFITS OF BIOTECH MAIZE PRODUCTION BY 2017
OFAB Kenya Publications