Hi everyone, I’m looking for some advice on a Cucurbita moschata population we are growing this year for the Farmer Stewardship Programme. I started this population about 4 years ago, mixing up several early fruiting varieties of butternut squash plus a few of Joseph’s moschata mix. Up until now it’s been very much a standard butternut, just with a diversity of shapes. I moved to Scotland from England last spring and we didn’t get any viable seed from the few fruit that ripened here last season (shorter cooler season, hence the adaptation project!) , but my friend Jayne in England had huge sucess and saved plenty of seed, luckily. This year we’re growing the seed she saved, but the population is looking very very different, see pictures! A few folks across the uk are growing it and reporting a real mix of colours and shapes. She didn’t have any other moschata growing on her farm, but did have a hulless ‘naked’ pumpkin growing nearby, but we thought this was C.pepo so would be ok. My question, is this just a frenzy of genetics expressing themselves in this generation, or do folks think there’s been some inter species hybridisation?? No idea what these will mature like or taste like…time will tell I guess!!
Looks like mix up in seeds. First 3 look definite maximas and the last definite moschata. Nothing to suggest any interspecific hybrids of any kind. Certainly not moschata x pepo.
I agree that the first three are definitely maximas. They have even, round stems attached to the fruits and the leaves are round/ evenly green. Fourth is a moschata. the fruit stem is like a pentagon and moschata flowers look distinct with thin “leaves” around them
Thanks all. It’s been driving me to distraction as I sowed the seed and was certain there hadn’t been a mix up. It’s the only moschata seed saved and sown on farm. But your comments prompted me to back track and investigate further. Some of our squash seedlings were eaten by rodents just after germinating this spring, someone on the farm gapped up cells by resowing fresh seed on a day I wasn’t around, I think what’s happened is they’ve sown maxima into empty cells in the flat containing the moschata population!! Either that or the rodents have moved seed around. Either way it explains what’s going on!! Thanks for your comments
There are still around half a bed of clearly moschata plants so all is not lost!
Some signs of interspecific cross:
The male flowers can avorted or can be less frequents and they are less rich in pollen.
The plant will product more fruits.
The most part of time the fecondation of one fruit required the male flower of a other plant.
The seeds of the fruits are partially full, they seem flat.
The fruits contains a little seed quantity.
The germination can be difficult.
That part is very far from being a systematic “sign” in my experience
Hello,
To be honest, nobody—not even you, the growers in the UK—knows for sure who the exact pollen donors were in that open-field chaos.
Rules are rules, and tables are useful in many cases, but sometimes nature doesn’t know it’s supposed to follow rules, and sometimes we fail to recognize the subtle, hidden details beneath what seems obvious.
Unlike the other commenters, I do not believe the first three photos represent typical, 100% C. maxima. They display its traits, but there is also something of C. moschata present. Based on morphological features, especially the stem (peduncle), the first three fruits are not pure C. maxima but rather an interspecific cross, as evidenced by the hard, sharply five-angled peduncle. The fourth fruit exhibits a morphological chimerism, where the five-angled stem and the wrinkled texture indicate a C. moschata influence, while the density and resilience of the tissues correspond to C. maxima.
What happened here is absolutely amazing, far more exciting than just maintaining a standard, isolated C. moschata grex. Through spontaneous, unmanaged crossing, vital maxima pollen pushed its way into the moschata grex, and furthermore, the result is viable seeds with a diverse segregation of traits. Simply a jackpot! And to top it off, not somewhere warm, but in the British Isles. Congratulations!
I am attempting interspecific squash crossing myself, and your victory fills me with hope.
Last year, I spontaneously crossed the interspecific hybrid Sprinter F1 (as the mother) with C. maxima. I harvested three fruits with Automn Crown F1 (correction for clarity/my records) / Sunshine F1 and one unexpected fruit with Sweet Meat Oregon Homestead. Only one ripening fruit with Sunshine F1 remains. So far, all fruits have yielded flat, sterile seeds. If this last holdout happens to contain any vital seeds, they won’t be used this season, but they will definitely reinforce next year’s polycross with genetic bridges.
That last fruit is verifiably, from the maternal side (Sprinter F1), one-quarter moschata and one-quarter maxima, and from the pollen donor, two-quarters maxima. So it is predominantly maxima (3/4), yet that mere 1/4 manifested in the stem—at first glance, you would say it’s a butternut squash.
If you look closer at the peduncles (stems), they are sharply five-angled and woody—a classic, dominant C. moschata morphological marker inherited from the mother, completely overriding the shape typical for C. maxima.
Instead of strictly separating species, we should welcome this. This accidental pollination broke the incompatibility barriers. And if you were to be so short-sighted as to consider this ‘miracle’ a failure, I would gladly adopt the seeds and use them in my own breeding.
*Where are the typical C. maxima traits here?*
I think you are going too subtle here. Having traits don’t mean they are direct interspecific crosses. The species have lived side by side for millenias and being able to cross quite readily, the changes of having “pure” squash species in those that are cultivated is next to zero. What you pointed out is just typical variation in each species. Whether it’s an earlier interspecific cross or convergent evolution is irrelevant. In my opinion, to be interspecific cross, it would have to be fairly clear in between rather than something that you really have to look for.
Like modern humans are on average 2% neanderthal and many people have traits of neanderthal, if you know what to look for, not to mention all those genes that aren’t making visible difference. Modern humans are therefore interspecific cross, but as there are no “pure” species, the interspecific cross (with 2% neanderthal) is the norm. So similarly in the squash interspecific cross is the norm if you count trace amounts, and therefore it’s pointless to call those interspecific crosses when you still can make 50/50 crosses or back crosses. You need some line to differentiate new crosses from ancient.
From a historical perspective, you are certainly right; spontaneous crossing between these species occurs quite rarely. However, my view is based on three distinct points: 1) Growers in the UK were originally cultivating a pure C. moschata grex. 2) The provided photos clearly display a mix of both maxima and moschata traits. 3) I have my own direct experience growing interspecific squash hybrids, and I am currently preparing a massive polycross project utilizing interspecies bridges and ‘smuggling non-crossed genes through the chaos’ of a pollen cocktail.
So, it seems we are just looking at this through different lenses.
Regarding points 1 and 2: If they were growing a C. moschata grex in the UK, and nobody took away or replaced all of their seeds, how do you explain that this moschata grex suddenly started exhibiting maxima traits along with this amazing diversity? I believe this is a clear case of segregation after crossing—genetic traits splitting up after a wide cross, rather than just simple F1 hybrids.
And what about my own interspecific cross from last year, will you just dismiss that? My maternal line was the interspecific hybrid Sprinter F1 (C. maxima x C. moschata), which exhibits total male sterility. What is the logical conclusion here?
Of course, there is always a small chance that I am wrong; I have only been into plant breeding for a short time. Perhaps someone like Joseph Lofthouse, who has substantially more experience with interspecific hybrids, should weigh in on this. But whatever the case may be, I have an enormous interest in obtaining some samples of those British seeds (I hope this request doesn’t violate any forum rules).
I don’t think any of the plants here are interspecific crosses. I’ve grown all cultivated Cucurbita species(except for ficfolia and argyosperma) for a very long time and I’m pretty confident the first three are pure maximas. Here are the traits that support this claim:
- The leaves(that you can make out) have a more round shape(not nearly as deeply lobed as pepo or moschata) and they don’t show any variegation(most cucurbita pepo or moschata will have at least weak variegation while most maximas completely lack the trait) The leaves in the image look exactly like pure maxima leaves
- The fruit stem is segmented into clearly visible lines(This is only the case for Cucurbita Maxima!) and it is mostly round(not every fruit will have a perfectly round stem because it will vary a little bit from how the fruit develops and what genetics the plant has). Overall the fruit stem looks exactly like a typical maxima stem.
- The fruit resembels a typical maxima kabocha/ kuri type fruit
In contrast, I can confidently say that the 4th image is a pure moschata. It is clear because of the hairy, thicker “leaves” surrounding the closed flower. This feature is unique to moschata and the flowers stand out when compared to pepo or maxima flowers.
The fruit with the long seedless neck(also only really found in moschata cultivars) also has a distinct, hairy, not segmented, pentagonal stem.
The first 3 images have exactly the same or very similar leaves and fruit stems typical of c maxima while the fourth image is completely distinct with different flowers, fruit stem and stem. I can’t see how any of these plants are the result of an interspecific cross or segregation as their traits are perfectly normal/ consistent with maxima / moschata and they dont really show any segregation in leaf and fruit stem genetics
It was already explained by original poster that there were some seeds sown later by a another person (which maybe didn’t know what to sow) to patch those that had not germinated. So there is no need to find another explanation. And I don’t see that there are any signs of interspecific crosses, just “pure” species with natural diversity. If I go and look through seed catalogue, those same traits pop up regularly in heirloom varieties.
That wasn’t the question here now was it? I didn’t comment on that. One picture with dried up stem isn’t much. You would have to be really careful not to make mix up while making the cross. If you don’t close male flowers before they open, they could carry also pollen from other species that insects have brought there. Even without, there is always change that other pollen gets there while making the cross. That’s why it’s really F2 onward that will tell you what you have, if you grow that in isolation. You should get plants that look like mostly either parent species and everything in between. Also it would be better that the cross was made with staple varieties, otherwise you will get variation where you can see whatever you want to see. Squash are even within species so varied that you will get single traits that might be interpreted to be from other species when they might at most be sign of a distant cross.