As I think I mentioned perhaps 4-5 years ago, that so many of my favorite apples are triploids. In an orchard with numerous triploids, which diploid apples have a reputation for being good producers of fertile pollen for apple production?
In Tom Burford's Apples of North America (Timber Press, 2013), he did specifically mention three that I have noticed. One is 'Grimes Golden' (putative parent of 'Golden Delicious') as "...self-fertile and is an excellent pollinator for other varieties. Another is 'Shockley', which he states: "...was a remarkable pollinator for other varieties.... My nearby 'Ribston Pippins', which are notoriously difficult to pollinate, always produced full crops." [..To which I add: YES, they are notoriously difficult to pollinate.] Third, in describing 'Yates', he says that "This vigorous tree bears heavy crops annually and is a good pollinator." Thankfully, Tom used the term "pollinator" rather than the horticultural world's term of "pollinizer" which has always irked me. Anyway....
Apparently, in some northwest orchards they use the crabapple "Transcendent" to pollinate commercial crops. It seems that it's a good source of abundant viable pollen in the orchard. Quite some years ago back at the Olympia (WA) farmer's market, someone was selling the small, ripe 'Transcendent' apples. They weren't at all bad in taste, but it was nothing to "phone home about".
Here, I'm curious to hear about other potentially good diploid apples that are proven to be good pollinators for the other more obstinate Triploids. Obviously, overlap of flowering time plays a vital part, but I'm open to the voices of experience and observation.
Crabapples in general are used as pollinators. Another particular variety that is said to have heroic pollinating effects is Winter Banana.
Dito Winter Banana. William's Pride is our package addition as it has a very long bloom period and attractive large flowers.
Thanks for the responses, folks. I most definitely appreciate it. When it comes to crabapples, we've got plenty of mature native crabapples (Malus fusca) on the property that seem to get the job done when all else fails.