Late night plant breeding rants kinda came about by accident. I get off work late and it's far enough into winter that I've been thinking of garden plans for the next growing season.

They're a bit disorganized, and kinda wander, but mostly follow a theme.

Let's go with onions.

"Onion" broadly refers to a range of species in the genus Allium.

A. schoenoprasum is onion chives.

Allium fistulosum is the Welsh onion (or Japanese bunching onion, etc).

A. cepa is the common onion.

There's others called shallot, ramps, etc.

Allium x proliferum, the topset onion (or Egyptian walking onion, etc) is an ancient hybrid between A. fistulosum and A. cepa. https://link.springer.com/article/10.1023/A:1008647700251

Topset onions are largely sterile, but it seems like every now and again they can produce seeds. https://treeonions.com/air-onions-finnish-walking-onions

One could potentially recreate the hybrid. They'd largely be sterile, but you could produce distinct varieties by using distinct varieties of the parent species.

That might be a fun project.

However, what I've been playing with falls squarely within Allium cepa. Historically, various names have been applied to this species.

These days a couple names are used.
"A. cepa var cepa" for the common onion and "A. cepa var aggregatum" for various shallots & potato onions.

"Potato onions" are called such because the bulbs are saved from year to year and replanted. Common onions are grown yearly from seed, for comparison.

Potato onions were much more common historically, but have largely fallen out of favor. They propagate slowly compared to seed-grown types.

One bulb planted will divide into a handful over a season. It would take years to scale up to a field. (Older varieties rarely made seed.)

One seed can lead to hundreds of seeds at the end of the year. Hundreds to thousands the next year.

The inevitable accumulation of viruses in the clonal bulbs being saved for propagation would lead to their decline over time. This paired with how rarely produced seeds and limitations on their propagation led to them falling out of favor.

A few years ago I received seeds produced from potato onions. Every seed grown produces a new variety. Most don't survive the winter or fail to produce bulbs, but a few from each batch planted persevere. https://twitter.com/thebiologistisn/status/1316617774249041920

I've been trying to multiply up the more successful varieties so far. Some bulbs don't survive a winter or don't multiply during a summer.

I need to have a significant amount of bulbs before I'll be comfortable making a meal from a variety. It'll take years to have any to share.

The good news is these new varieties are much more prone to produce seeds.

Last spring I collected a large number of seeds from the most successful new varieties so far.

Next spring I'll be able to grow out hundreds of seeds.

So far, my population has been almost entirely white/yellow onions. One seedling which didn't make it looked somewhat pink. I'm hoping I can find more like it.

Eventually I may try to cross in a typical red onion, to get more color. This would toss in lots of genetic diversity.

Many from the initial batch of seeds I received didn't produce bulbs at all. I'm hoping those grown from this new batch will have a much better propensity to bulb.

Over the next few years I'll select for those varieties which are best able to survive my winters & most able to increase in size during my summers.

Eventually I may come to have a consistent variety that can readily be grown from seed, but also from saved bulbs.

Potato onions also differ from common onions in how they bloom.

When common onions bloom, the stalk arises from the center of the existing bulb. This draws energy from the bulb, shrinking it. The bulb then becomes unusable for food.

When potato onions bloom, the stalk arises from a side bud at the base of the bulb. The growing stalk doesn't drain and shrink the bulb, so the bulb remains usable (even though it might be a bit smaller than otherwise).

A seed-grown variety with this style of blooming would produce a more consistently usable crop, while producing seeds (& bulbs) to plant the following year.

There's a lot about onion biology I don't know. I haven't produced enough plants to get a good feel for what potential they have, but I've seen hints.

Most varieties grow new bulbs which remain attached at their base, leading to a "nest" of cramped bulbs pressed together.

One of my new varieties instead has bulbs which separate and crawl sideways through the soil via contractile roots. The new bulbs are smooth and rounded.

Unfortunately this variety isn't fully winter hardy here, so I have not been able to produce more than a few.

The onions I've produced so far seem to vary from sweet to pungent, based in their scents. I haven't eaten any yet, so really, who knows.