Not as easy a question as you might think. The closest thing to scientific testing I know about is Jim Ankerson's rope cutting tests, and those rate ZDP189 as significantly better at edge retention than HAP40. At cutting rope. Which can be extended to many abrasive materials, like cardboard. But, not fruit.
A number of caveats, however. Geometry is the single most important factor. Then there is the hardness and heat treat, which can vary widely (my William Henry's ZDP is way hard). Then there is your ability to sharpen the edge and maintain it. To say nothing of your actual usage versus cutting abrasive materials.
So, from a purely edge retention POV, the ZDP189 is probably the right choice. However, as I and many others will attest, getting HAP40 screaming sharp is relatively fun and easy compared to ZDP189.
Worse, all that stuff just my opinion and experience. Other people have different opinions, many of which are undoubtedly valid.