A great disadvantage of introduction as a method of crop improvement is the

Introduction as a method of crop improvement involves bringing in a new variety or species of crop from a different geographical location to an area where it was not previously cultivated. One great disadvantage of this method is the introduction of a new type of disease into the new area of cultivation. The introduced crop may carry pathogens or pests that are not present in the new area, which can lead to the spread of diseases that can be harmful to both the introduced crop and the local crops. This can cause significant economic losses and affect food security. Therefore, it is essential to carefully screen and quarantine any introduced crops to prevent the spread of diseases.