Lapiedra martinezii and Vagaria parviflora are two species closely related to Narcissus, though not as closely as those in Sternbergia. As the former two are blooming now for me, I collected their pollen and attempted pollinating them with Narcissus pollen to see if any seeds might come of it.
So far I have tried paperwhite, bicolor tazetta, and poeticus pollen on them, with no seed set. L. martinezii does set seed if the anthers are not removed, but the resulting seedlings appear not to be hybrids, suggesting that L. martinezii is self-fertile. In the past, I have also attempted hybrids with a commercially available selection of Sternbergia lutea, also with no seeds resulting.
Possibilities for future crosses may be to use L. martinezii and V. parviflora pollen on Narcissus species or cultivars. Other species I would like to work with are Vagaria ollivieri, Hannonia hesperidum, and Sternbergia colchiciflora, but I do not currently have them to work with.
Why attempt these in the first place? I think at best any successful outcomes would be curiosities more than good garden flowers. On the other hand, V. parviflora has beautiful foliage with a prominent white stripe and L. martinezii has a light but wonderful fragrance. To combine these with positive traits of daffodils might make something beautiful.
Lapiedra martinezii
Vagaria parviflora pollinated with pollen of different daffodil species