Step 1: Understanding the Concept:
Hybridization challenges in mango breeding stem from its high levels of heterozygosity, polyploidy, and complex floral biology.
Step 2: Detailed Explanation:
- Assertion (A) is true: Combining regular bearing, good fruit quality, attractive color, fiberless pulp, and disease resistance in a single cultivar is difficult due to high heterozygosity and severe inbreeding depression.
- Reason (R) is false: Mango (Mangifera indica) is a highly heterozygous (not homogeneous) and allotetraploid ($2n = 40$) (not diploid) crop. This makes the statement in the reason incorrect.
Step 3: Final Answer:
Assertion (A) is correct, but Reason (R) is false.