How does seed dormancy differ?

• A. Primary dormancy occurs after harvest when conditions become unfavorable.
• B. Secondary dormancy is the innate inability to germinate at harvest.
• C. Primary dormancy is the seed's innate inability to germinate under favorable conditions at harvest; secondary dormancy occurs after harvest when conditions become unfavorable.
• D. There is no difference between primary and secondary dormancy.

Answer: (C)

Seed dormancy comes in two forms that differ by timing and cause. Primary dormancy is the seed’s inherent inability to germinate even when conditions look favorable at harvest because the seed’s physiology keeps it from waking up. This dormancy can be broken later by processes like after-ripening, stratification, or scarification, which gently shift the seed toward conditions that allow germination. Secondary dormancy, on the other hand, happens after harvest when environmental conditions become unfavorable—drought, heat, or other stresses—that push the seed back into dormancy even if it could have germinated earlier. That distinction is exactly what the correct statement captures: the first form is an innate state present at harvest under favorable conditions, and the second form arises after harvest due to unfavorable conditions. The other options mix up the timing or the nature of the dormancy, which is why they aren’t correct.