Summer squash seed saving and landrace

I collect a lot of own seeds, but  have stopped colecting seeds of summer squash. My previous experience was that varieties cross easily and in order to keep a variety "clean" flowers need to be protected and hand-pollinated. In effect I was getting some offspring that was producing very bitter fruits, due to high cucurbitacin content I suppose.

My question is - is there a way to develop a local landrace of summer squash without a risk of getting bitter fruits, or it is rather ony a selection of seeds from specimens that are not bitter?

Ah, those pesky pepo squash!

Bitterness in pepo summer squash is likely to come from the decorative gourds (which are the same species). I hear rumors that the wild, non-domesticated gourds still grow feral in some areas of the eastern usa.

It's easy to eliminate the decorative gourds from my own garden. More difficult to eliminate those that are feral or growing at nearby neighbor's.

My protocol for eliminating bitterness in squash is to wait until nearly every squash has a fruit, then go out and taste fruits from each plant. Any plant that has a bitter fruit is culled. Any plant without fruits is culled. Then every fruit in the patch is picked, so that all new fruits will only be pollinated by non-bitter parents.

Another protocol that might work, is to taste the cotyledons of each plant, and cull any that are bitter. That works with cucumbers, and they are so closely related to squash, that I bet it works the same in both species.

Two great tips, thank you. The only problem I see here is what you have mentioned - plants grown by neighbors, and bees transferring pollen.

The pepo squash were a pain for me. Because I wanted to keep my beloved "pure" varieties. I like my yellow crookneck to be exactly crooked, and exactly yellow. I grew ten different varieties, and allowed them to cross pollinate, so there was diversity in leaf shape/color, and perhaps other unseen traits. But I kept the yellow and the crook.

With zucchini, I didn't care what color the skin of the squash was, but I cared that it was always long and skinny.

And  like everything I grow, I cared about flavor. Tasting every fruit before saving seeds from it. If anything is the slightest bit off, I don't save seeds from it.

It was easy for me, to keep lots of "varieties" of pepo squash, because I was growing in 6 fields in 4 communities. These days, I only grow one variety per year, because I am growing in a single field. I'm not willing to do the extra labor required for hand pollination.

I could make life easier on myself by giving up on my desire to hold onto my beloved shapes and colors. Any (non-bitter) pepo squash can be eaten as a summer squash if it's picked while young and tender.

I grow an acorn/delicata winter squash grex. I select for awesome flavor, regardless of the shape or color of the fruit.

Joseph Lofthouse wrote:
Another protocol that might work, is to taste the cotyledons of each plant, and cull any that are bitter. That works with cucumbers, and they are so closely related to squash, that I bet it works the same in both species.

Wow!  That is a great tip. You've just saved me a lot of work. Thanks Joseph

Pollination is a highly localized phenomenon. Flowers are highly likely to be pollinated by the closest flower to them that is compatible. Here's what the math looks like when two ten foot long rows of carrots are planted ten feet apart. There is a minuscule amount of mixing between them. That might matter to a mega seed company growing seed by robots for an entire nation. It doesn't matter for a home gardener that looks lovingly at every plant, and tastes every plant before saving seeds from it.

Joseph Lofthouse wrote:The pepo squash were a pain for me. Because I wanted to keep my beloved "pure" varieties. I like my yellow crookneck to be exactly crooked, and exactly yellow.

That's my problem exactly as well - growing in a small homestead garden, that limits possibility to keep many varieties, if I wanted them to stay pure. Perhaps the route you describe further is a better one - stop being a collector of varieties, focus on a good taste and nice harvest only.

I have been observing my bees, they seem to visit all flowering squashes in the same time, so it might work a bit different than in case of rows of carrots, but nevertheless seeing pollination as localized event is encouraging to try saving seeds based on taste only.

I have just realized that you have said one thing which is entirely different than what I have always thought - I was thinking that bitterness apears only in the offspring (F1 generation). When pollen from plant A goes into a flower of plant B, the fruit is not bitter yet, only when I plant the seeds from this fruit next year, it might be bitter. If it is correct that only bitter fruit produce seeds that grow into plants that give bitter fruits next year, that would be way simpler than I thought. Am I missing something here?

That chart corresponds exactly with what I see in my crops that are primarily pollinated by bumblebees.  Those include my squash, melons, beans and sweet potatoes. The bees are not dumb, they don't fly around willy nillly. Instead they visit flowers in the order presented to them.

It's easy to cross even difficult plants like beans just by planting different ones in immediate proximity. Two pole beans for example will yield crosses if planted on the same pole. That is assuming you have plenty of bumblebees. A twenty foot row, with ten feet each of two kinds will yield crosses where the two meet but not at the ends.  

I'm not sure other pollinators are as methodical about it but still it appears to me that even in the case of wind pollination most plants are mostly crossed by their immediate neighbors.

Well, bees are way more "mobile" than bumblebees as far as I can see. A single bee visits roughly 100-150 flowers per flight,  I'm not sure if I have that much flowers of one variety in my garden at once. That's perhaps why I see them flying from one variety to another. I should probably reduce number of varieties and increase distance between them.

Richard Gorny wrote:I was thinking that bitterness apears only in the offspring (F1 generation). When pollen from plant A goes into a flower of plant B, the fruit is not bitter yet, only when I plant the seeds from this fruit next year, it might be bitter. If it is correct that only bitter fruit produce seeds that grow into plants that give bitter fruits next year, that would be way simpler than I thought. Am I missing something here?

The bitterness gene is carried by both the mother, and the pollen donor. It is a dominant trait, and easy to identify. If a seed of a non-bitter mother is pollinated by a bitter father, then the offspring will be bitter. We can taste bitterness early in the season, and eliminate bitter plants, before allowing the non-bitter plants to cross pollinate. Dominant traits can be eliminated in a single growing season.

In general, my philosophy is that it's easier to start with carefully selected parents, than it is to clean up a mess. When I first started growing landrace style, I cast a wide net to bring in lots of wild, or semi-wild genetics. I paid for it with funky flavors, and traits that are not well suited to agriculture. Took a few years to clean up those varieties.

For people just starting with landrace growing, I recommend sticking with great varieties. When great parents cross, they tend to produce great offspring.

Fantastic, one more question if I may. Here in Poland the seeds of Acorn squash are really hard to find, usually we have to buy them abroad (not sure why is that). In majority of cases these seeds of Acorn squash than can be purchased are F1 hybrids. Is such hybrid a good starting material to follow your route, for instance to let it cross-pollinate with Delicata (frequently grown here) and then select for desired taste?

Instead of watching hoards of pollinators, watch a specific bee. Reed's observation that they fly to the closest flower is spot on. In the case of carrots, they take a partial step to the next closest flower.

From a purely mathematical perspective, a bee that is collecting pollen from the next closest flower is the most efficient at gathering food and pollinating flowers. Long flights take a long time, bees that are making long flights are tremendously less effective pollinators. It saves energy, and increases pollination efficiency to do lots of little hops.  

Wind is the same. The dilution factor is tremendous. A small increase in distance adds up to a huge dilution. Pollen is much more likely to blow to the closest flower, than to drift in on the wind.

F1 squash seeds are a fantastic starting point for landrace growing.

One thing that can be done to keep semi-purity, is to plant Acorn on one end of the row, and Delicata on the other end on the row. Then save seeds from the ends but not the middle. The Acorns will mostly pollinate themselves, and the Delicata will mostly pollinate themselves. Separating them into opposite corners of the garden can dramatically limit the amount of crossing between them.

Great tip, thank you.

If I cull bitter squash, whether plants or fruits, and feed it to my chickens, will my chickens' eggs be bitter?