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Bioscience in brief

New plant technologies

What are the advantages of gene stacking?

Stacked GMOs are an important part of integrated pest management (IPM) strategies to delay the development of herbicide-resistant weeds, and to defer the breakdown of the resistance provided by the transgene/s against insect pests.

Why? The probability of a weed or insect pest developing resistance to different unrelated insecticidal or herbicidal compounds is much lower than to a single compound. This is because it requires independent gene mutations occurring simultaneously in the weed/pest.

The challenges facing a crop in the field include multiple pests and diseases as well as adverse environmental conditions such as drought, heat and cold temperatures. Gene staking allows the development of crops with combined protection against several of these challenges.

GM maize with improved tolerance to drought was approved for cultivation in the USA in 2012. It is sold as GM stacked hybrids also comprising insect resistance and/or herbicide tolerance traits. Maize varieties with improved water-use efficiency (Water Efficient Maize for Africa) are currently being developed by conventional and GM methods in a number of East African countries.


For the occurrence of certain characteristics in a crop, the activity of several genes in the same biochemical pathway would be required. Good examples are Golden Rice, or oilseed crops containing “fish oils” (omega-3 long chain polyunsaturated fatty acids found in algae and oily fish) that are essential for human development.

Developing healthy seed alternatives with novel plant oils.