Insect resistance breeding is more difficult, because:

Correct option is A

What Is Insect Resistance Breeding?
Insect resistance breeding aims to develop crop varieties that can tolerate or resist insect pests, minimizing yield loss.
Resistance can be due to:
Antibiosis (affects insect biology)
Antixenosis (repels insects)
Tolerance (plant withstands damage)
�� Why Is It Challenging?
In contrast to disease resistance, where pathogens often show strict host specificity, insect pests:
Can attack multiple hosts
Have broad feeding ranges
Show variability in behavior and adaptability
✅ This lack of host specificity makes it harder to breed consistently resistant varieties, as the same insect may behave differently across crops or regions.
�� Explanation of Options:
(a) Host specificity is less marked – ✅ Correct, insects are less host-specific, complicating resistance breeding.
(b) Fairly simple inheritance – ❌ Would actually make breeding easier, not harder.
(c) Biological strains are less common – ❌ Insects often do have biotypes/strains, but this isn’t the main challenge here.
(d) Have complex inheritance – ❌ Some resistance is polygenic, but not universally true, and not the main issue.