Illinois Field Crop Applicators Practice Test

When a hybrid has defense mechanisms that limit infection, what is this called?

1. Tolerant

2. Resistant

3. Immune

4. Susceptible

The correct answer is: Resistant

The correct answer is "Resistant." In the context of hybrid plants, resistance refers to the inherited traits that enable the plant to withstand or limit the effects of pathogens, pests, or adverse environmental conditions. This resistance could be through various mechanisms such as thickened cell walls, production of secondary metabolites, or other biochemical pathways that deter infection or damage from a specific threat. When a plant exhibits resistance, it can maintain its health and productivity even in the presence of pests or diseases, making it a crucial characteristic for breeding programs aimed at developing robust crop varieties. While the other terms are relevant in discussions of plant health, they denote different relationships between the plant and threats. For instance, tolerance pertains to a plant's ability to endure some level of damage without significantly affecting its overall health or yield but does not mean the plant actively prevents infection. Immunity implies a complete inability to become infected, which is rare in agricultural crops. Susceptible indicates a vulnerability to damage or infection, meaning the plant can easily be harmed by pests or diseases.