Step 1: Radish varieties.
Pusa Chetki is a famous early maturing radish variety developed by IARI, hence A → III.
Step 2: Brinjal varieties.
Pusa Purple Long is a widely cultivated brinjal variety, hence B → I.
Step 3: Tomato varieties.
Pusa Ruby is a popular tomato variety, hence C → II.
Step 4: Pea varieties.
Pusa Pragati is an improved variety of pea, hence D → IV.
Step 5: Conclusion.
Thus, the correct matching is A - III, B - I, C - II, D - IV.