Final answer:
Limiting random sexual reproduction in food crops is concerning because it decreases genetic diversity, increasing vulnerability to diseases and reducing the potential for crop improvement.
Step-by-step explanation:
Many farmers are concerned about the decreasing genetic diversity of plants due to generations of artificial selection and inbreeding. Limiting random sexual reproduction of food crops is concerning because it leads to a reduction in genetic diversity, which is crucial for maintaining disease resistance and the overall fitness of crop populations. The correct answer to the question is 'a) It reduces resistance to diseases.' When crop plants are too genetically similar or closely related, they are more vulnerable to being wiped out by diseases, as these diseases can easily spread among them. Moreover, in scenarios where wild species are lost, it becomes difficult to introduce new gene variants that could enhance the resilience and yield of crops through breeding with existing varieties. This genetic homogeneity ultimately limits the potential for future crop improvement and the continued security of our food supply.