I thought a lot about solanum pollinators last year.
What started it was, I had a ton of solanum peruvianum planted. They flowered prolifically all summer but not a single one set fruit. They were gorgeous plants! But I suspect they were not being pollinated. They were between a corn and a squash patch, so there was lots of cover, and the row butted up against m neighbour’s unmaintained pasture, so there should have been space, but not a single one seemed to set fruit.
Then, I have a pretty high exserted stigma rate, my climate seems to induce stress exsertion at the beginning of the season in nearly everything. I don’t have a high cross rate. I’d think there are native pollinators which come out despite the cool weather – there are some that do my haskaps fine even in the frost – but they don’t seem to move pollen on my solanums.
Granted, I don’t seem to have a high pollen production rate here either.
I’m starting this thread for a bunch of thoughts on solanum pollinators:
Who are they?
How can these specific creatures be encouraged? Overwintering habitat? Other food species for them? Physical environment, for instance, lots of cover?
Also maybe, what causes low pollen production?
Sorry that I can’t help, but, I wanted to ask if you’ve crossed S. peruvianum with domesticated tomatoes? I don’t seem to be hearing anything about people using them, I’m surprised they don’t seem to be part of the promiscuous project for example… I might bring this up on the other thread…
Where I live a native bee, the blue banded bee, is a solanum, especially tomato, pollinator. They are like a small bumblebee and buzz the flowers to extract pollen. I’ve never noticed a honey bee on any of my solanum flowers (tomato, eggplant, chilli, ground cherry, potato).
I grew Peruvianums in my own greenhouse, in a friends greenhouse, and in the field. In my friends greenhouse they were giant and beautiful,a tons of showy flowers, not a single fruit. in my own greenhouse there were tons of fruit, they tasted like tiny melons, very fun. In the field they were cold, had plenty of fruit that weren’t very tasty (didn’t sufffer from lack of fruit set like heirlooms did). I noticed in my own greenhouse that my neighbors bees loved them. They would buzz around all the wild tomatoes constantly, as soon as they got within 6 inches of a domestic tomato they would go back to the wild tomato. Some bumblebees too, have a video of that here.
I dont think there is much cross pollination early in the season because there just aren’t many flowers to attract. So if you save seeds only from first few there aren’t going to be many crosses. I have noticed that there are quite a lot of bumble bees going through them once they are in full bloom. Even then it would need suitable flowers for likely cross pollination. As for your peruvianums, they must have been too isolated. In one unrelated documentary there was about study of bumble bees and they have learned routes that they follow. So they dont wander around your field, but fixed points they have learned during the season and if nothing changes they will follow that route. So you might need to teach them with something that flowers earlier next to your peruvianums.
Bumblebees love my potatoes. There are honey bees in hives next to the field but I don’t see them much in solanums. @Greenstorm you don’t have bumblebees?
We do have bumblebees! This year I saw my first queen bumblebee on my apple tree, and they were pretty prolific on my favas near the peruvianums. My peruvianums sound like those in your neighbour’s greenhouse, tons of flowers but no fruit. And I was watching so closely for those first fruit, but the flowers just browned and fell off. Do I remember that, unlike normal tomatoes, they required outcrossing?
I have a friend who’s really into bees, I should probably ask her about what is around that fits the bill.
Bumblebees, Carpenter bees, and Digger bees are prolific pollinators of solanum peruvianum at my place. There are lots of other species that also fuss with the flowers. Here’s some photos. I’m not an entomologist, so I might misname the creatures.
I can tell that a flower has been visited by an insect, cause the anther cone turns brown from bruising.
Tomato flowers do not have nectaries, therefore, honeybees tend to ignore them, but not always.
Solanum peruvianum is a 100% out-crossing species. It cannot cross with close relatives. If too few plants are grown, that are too closely related to each other, then they may not set fruit. There may be environmental factors that interfere with fruit set: too hot/cold, wet/dry, thrips eating pollen, etc.
I don’t often recommend minimum population sizes, except in the case of the self-incompatible tomato species, There are about 35 alleles responsible for the self-incompatibility mechanism. If we split those evenly between plants, without any duplication, a minimum of 18 plants would be required. Maintaining a diverse population might require around 100 plants. Sure, a population can exist, with as few as 3 alleles, but pollination would suffer.
Solanum peruvianum is incompatible with domestic tomatoes, so it is not commonly used in breeding projects. Once in a while, a cross may occur, but it’s highly unusual, and can’t be relied on.
Oh! All my seeds were from @julia.dakin last year, I wonder if they were too closely related. I had maybe 20 plants at most.
This year I’ll keep an eye on the anther cones for bruising, and I’ll maybe try to find a second source for additional seed. I’ll try planting in two places on the property too, to see if I can catch pollinators better in one or the other.
Amazing the lengths we’ll go to to taste an intriguing-sounding fruit. Though they were super beautiful. Maybe I can convince my neighbour to put some in his flower bed too.
Such a strong self-incompatibility system is a great argument for sharing seeds with all your neighbors, everyone growing them, and everyone sharing their seeds with each other. And over the Internet, too!
That plant behind him really got away from me and took over everything…
