Hey Tyler! Moringa oleifera is highly cross pollinated due to being pollinated by insects, especially bees, and due to the delayed stigma receptivity of the flowers. I haven’t found any definite isolation distances for Moringa oleifera, but based on vegetables that are insect pollinated, the isolation is at least 1/2 mile - 1 mile (at least) to maintain the purity of the variety. One site I read said 500 m (0.3 mile) isolaton distance for Moringa oleifera. Unless you have a field isolated by a mile or two from other trees (even your neighbors’ trees), it will prove to be difficult to maintain the purity of a variety.
I’ve seen quite a bit of variation even within Moringa oleifera “varieties”. The PKM-1 and PKM-2 varieties each come from a cross of 2 different varieties and have shown variation in the offspring. So, perhaps instead of focusing on producing a variety, you could select the trees that have the characteristics you want, rogue out the off-types, and allow the ones you’ve selected to cross-pollinate with each other. You may even collect seeds from those trees and plant them and do another selection. The issue is still if your neighbor has moringa trees. But in this way, you select for characteristics that do well in your area and in a way produce your own locally selected “variety”. I am putting variety in quotes because of the variation I’ve seen even within named varieties (probably due to cross-pollination).
Cross-pollination and therefore wide isolation distances are a limiting factor in producing seeds of pure Moringa oleifera varieties.