Whitefly-transmitted (WFT) geminiviruses are recognized as the most widespread and most severe viral pathogens of cotton, and vectors are increasingly developing resistance against presently used chemical pest control methods. WFT-geminiviruses are known to cause, inter alia, cotton leaf crumble disease, cotton leaf curl disease and other leaf distortions responsible for severe cotton yield reduction. Based on existing knowledge and experience in the field of biotechnology and genetic engineering, research was undertaken to define and characterize the biological and genetic particularities of the WFT geminiviruses; collect, characterize and preserve germplasm resistant to cotton viruses; develop transformation and regeneration systems for selected cotton varieties; produce geminivirus-resistant genotype of cotton; make available geminivirus-resistant genotype of cotton to interested cotton growing countries for hybridization to develop commercial varieties resistant to virus attacks; produce a technical manual and disseminate the technology. The project focused on economically important WFT geminiviruses, in particular on the cotton leaf curl viral (CLCuV) disease, which has already caused massive damage in various cotton producing countries (e.g. Egypt, Nigeria, Pakistan and Sudan).