Q.Differentiate primary introduction from secondary introduction.

Step 1. Primary introduction occurs when the introduced variety is already well adapted to the new environment, so it is used directly without any alteration to its original genotype.

Step 2. Secondary introduction occurs when the introduced variety must instead be subjected to selection to isolate a superior form, and that form is then hybridised with a local variety to transfer one or a few desirable characters into locally adapted material. …

Contrast the two categories exactly as the chapter defines them und …

• Assuming both types involve breeding — primary introduction involves no genetic alteration at all. …