When digging and lifting seedlings yesterday morning, I encountered an unusual situation. I had planted one or two small bulbs of each of twenty sibling seedlings from the cross ‘Miss Primm’ x N. fernandesii three years ago in a rectangular patch one ft. by 2.5 ft. in one of my daffodil beds. These little bulbs had been transplanted directly from the box where they had been grown from seed for three years (in sterile soil mix). They seemed normal at the time they were removed from the seedbed. Yet in the past three years, every one of these bulbs had “horse-teethed” – turned into numerous slender bulblets, most still attached at the basal plate. Further, in the adjoining area where seedling bulbs from totally distinct crosses had been planted, some (but not all) of these bulbs were similarly afflicted!
This leads me to ask: “what is the cause of the horse-teething phenomenon?” I have heard two hypotheses: (1) it is genetic, and (2) it is a virus. The fact that every bulb of the ‘Miss Primm’ x N. fernandesii was affected might cause me to believe #1. But the affliction in adjoining bulbs would cause me to believe #2. If from virus, I have no explanation of its origin (I’ve not encountered horse-teething in my stocks of either parent), or of the vector for spread (subsoil nematodes? aphids?)
I’d like to learn of others’ experiences and insights.