Recommending GMO corn for areas under high pressure of pests

Corn yield only improved by 0.5 tons per ha after 10 years of application

Corn is an essential part of the Vietnamese crop production system, with the second-largest cultivation area following rice. In recent years, domestic maize production has made significant strides, particularly in the areas of hybrid corn breeding research, cultivation techniques, seasonality, technology, and market development.

Corn is, however, primarily farmed in regions with limited water resources, inadequate soil nutrients, rugged terrain, and mountainous regions. Vietnam's corn production is still fragmented and small-scale, with a low mechanization rate, an underdeveloped post-harvest technology, and inefficient fertilizer use that results in waste, all of which lower the overall effectiveness of corn production. Additionally, Vietnam continues to import a substantial quantity of maize kernels annually for the production of animal feed, as domestic corn production has not yet met the local demand.

Dr. Dinh Cong Chinh, citing statistics from 2015 to 2023, observed that the corn cultivation area decreased from nearly 1.2 million hectares to 884,000 hectares. The yield in 2015 was 4.48 tons per hectare; however, by 2023, it had only slightly increased to 5.02 tons per hectare.

Consequently, Vietnam's corn yield has only increased by 540 kg per hectare (an average of 54 kg per hectare per year) over the past decade, following to the introduction of genetically modified corn. In that time, the import rate increased from 58.8% to 68.6%.

"Upon reflection, the average annual increase of only 0.5 tons per hectare is very low! Genetically modified corn is highly promising; however, the issue of how to employ it to enhance productivity must be resolved shortly", the representative of the Department of Crop Production observed.

In regions with significant pest pressure, GMO corn varieties (GMO) produce higher average yields

MARD (Department of Crop Production) has recognized a total of 31 genetically modified corn (GMO) varieties as of September 30, 2024. This includes 30 GMO corn varieties that are derived from recognized parent lines under Circular 29 on silviculture measures and one GMO corn variety that is recognized under the Law on Crop Production and Decree 94, which guides the law on crop varieties and cultivation.

Proactively working with provincial Departments of Agriculture and Rural Development and Agricultural Promotion Centers in critical corn-growing regions, the majority of enterprises established demonstration models of GMO corn varieties following their official recognition.

These units conducted workshops, field evaluations, and model summaries prior to the construction of these models, organizing training and technical consulting for the planting of GMO maize at nearly all demonstration sites.

According to reports from companies, in the 10 years since 2015 (when the first GMO corn variety was recognized until September 30, 2024), a total of 13,256 tons of GMO corn seeds have been imported out of 72,141 tons of corn seeds (accounting for 22.5% of total imported seed volume), equivalent to 662,000 hectares of planted area (excluding the volume of domestically produced GMO corn seeds not reported to the Department).

All GMO corn varieties that are imported are planted in ecological regions that are recognized and contain genes that are resistant to Lepidoptera pests, including stem borers, ear borers, and tassel borers.

Dr. Dinh Cong Chinh cited local preliminary assessments, observing that these GMO varieties were well-suited to seasonal structures in Vietnam's corn-growing areas and exhibited robust growth. This was due to the genetic similarity between GMO corn and its parent lines in terms of key morphological characteristics.

The use of GMO corn varieties showed clear resistance to pest groups for which they were genetically modified in crops and regions with significant Lepidoptera pest pressure.

In contrast, the pest resistance traits of GMO corn varieties were not as apparent in regions that experienced little pest pressure from stem borers. In comparison to traditional and local parent varieties, the economic benefits in these regions were also unclear, as the cost of GMO corn seeds was higher.

In crops and regions with high pest pressure, GMO corn varieties produced higher average yields than traditional varieties in terms of yield and quality. The quality of commercial kernels was also higher to that of traditional varieties, as they were less susceptible to fungal diseases and stem borers.

However, in regions with minimal pest pressure, GMO corn did not exhibit significantly higher average yields than traditional varieties, and the quality of commercial kernels was comparable to that of traditional varieties.

As a critical crop in the process of crop structure transformation, MARD has identified maize (including sweet corn, biomass corn, and grain corn). There is a necessity for comprehensive, systematic, and long-term assessments of the effects of the widespread and extended use of GMO corn varieties.

Dr. Dinh Cong Chinh suggested that the biodiversity changes, specifically the quantity and composition of insect and animal species in maize-growing areas, as well as the ecosystem of plants closely related to corn, be the primary focus. Nevertheless, certain secondary pests may develop into primary pests, a potential hazard due to their lack of research on biology, ecology, or control methods. This occurs when the pests are initially difficult to manage.

The effects observed with insects may be also applicable to soil organisms. The direct or indirect effects on both humans and animals may result from the long-term, accumulated effects of using GMO products as food and animal feed over decades or even centuries. Furthermore, there are apprehensions regarding potential fraud and trade-related issues between GMO varieties and non-GMO progenitor lines.

The representative of the Department of Crop Production suggested that seed supply units should establish a close partnership with the provincial Departments of Agriculture and Rural Development to collect precise data regarding zoned areas and large-scale, specialized maize production regions shortly. This coordination will facilitate the planning of medium- and long-term development.

To construct a development plan for GMO corn that maximizes efficiency, they recommended carrying out comprehensive assessments of regions, seasons, and soil conditions in high-pressure areas and in low-pressure areas.

Only regions, seasons, and soil types with high pest pressure, where demonstration models have already been established, should be recommended for the planting of GMO corn. In regions where no demonstration models have been developed and regions, seasons, and soil conditions under high pest pressure have not been identified, farmers should not be encouraged to plant GMO maize. This would contribute to the reduction of input costs and the enhancement of economic efficacy.