Zim Tests GM Cotton

Zim Now Writer

Zimbabwe is advancing efforts to revitalise its cotton industry by evaluating the performance of genetically modified cotton varieties, signalling a shift towards biotechnology to increase productivity, pest resistance, and farmer profitability.

The initiative, led by the Ministry of Lands, Agriculture, Fisheries, Water, and Rural Development through the Cotton Research Institute, aims to position cotton—often called the country’s “white gold”—as a key pillar of rural livelihoods and economic growth.

Cotton supports over 400 000 households in Zimbabwe, creating employment and supplying vital raw materials to the local textile and oil-processing industries. In 2022, the country exported raw cotton worth US$147 million, ranking 16th globally. Major export destinations include Lesotho, South Africa, Mauritius, Pakistan, and Indonesia.

Under strict regulatory oversight, Zimbabwe has launched confined field trials of genetically modified cotton (Bt hybrids), comparing their performance against conventional varieties across five locations nationwide.

Dr Dumisani Kutywayo, Chief Director for Agricultural Research, Innovation and Specialist Services, said the trials tested four Bt hybrids (containing the Bollgard II gene), four non-Bt hybrids, and two local open-pollinated varieties.

The primary goal was to measure natural pest incidences—especially bollworms, including Helicoverpa armigera (cotton bollworm), Diparopsis castanea (red bollworm), Earias insulana (spiny bollworm), and Pectinophora gossypiella (pink bollworm)—and the resulting locule damage on cotton bolls.

Spraying thresholds were applied based on bollworm counts, with lower thresholds used for Bt hybrids due to their genetically enhanced resistance. For example, Bt varieties were only sprayed when five escapee larvae of second instar stage were detected, while non-Bt varieties were sprayed based on specific pest egg or larval counts per plant sample.

Preliminary findings indicate that Bt cotton varieties significantly outperform their counterparts in pest resistance:

Bt hybrids recorded the lowest pest incidences, roughly two times lower than OPVs and three times lower than non-Bt hybrids.

Locule damage was lowest in Bt hybrids at 19.9%, compared to 39.55% for non-Bt hybrids and 40.55% for OPVs.

While these results are promising, Dr Kutywayo emphasized the need for caution.

“These are still early results, and more data is needed before we can assess the full impact on yield and production costs. In the interim, no firm conclusions can be drawn from the trial results,” said Dr Kutywayo.

If proven successful, Bt cotton could usher in a new era for Zimbabwe’s cotton farmers, enabling higher yields, reduced reliance on chemical pesticides, and better income stability—especially for rural communities.

The cotton revival initiative aligns with Zimbabwe’s broader goals to modernise agriculture, stimulate rural economies, and strengthen food and fibre security through science-driven innovation.