A Better White Pumpkin?
White Pepo aka Cotton Candy was introduced to commerce by the Rupp Seed Company. It's a nice cream colored pepo type pumpkin (C. pepo) with some intentional variability in size, ideal for farmstand Halloween sales where this novel color introduction displays well beside traditional orange pumpkins. It has tender easily bruised skin (imperfections show up more on the white surface) with white flesh and a large seed cavity suited for carving. It's handle is not firm and long lasting though. The skin can darken exposed to the sun from cream to a creamy yellow color. Although not considered a prime edible squash, the flesh is crisp and can be shredded to make a fresh salad like cabbage slaw. It is generallly considered tasteless and like a spaghetti squash (which it might resemble to some), takes on the flavor of the seasoning. There are other white pumpkins commercially available including a few maxima type (C. maxima) pumpkins like "Casper" which are significantly different in characteristics to Cotton Candy.
We crossed Cotton Candy with Baby Boo in 2005 to produce an F1 (Ghost!) which was distributed through the OSP (Organic Seed Partnership) to participating organic farmers in New York State in 2006 and 2007. The diminuative Baby Boo, a patented Jack-Be-Little type with long lasting white skin is a popular fall decorative squash and like Cotton Candy is an open-pollinated variety (non hybrid). Cotton Candy and Baby Boo are the parents of the Ghost! tribe that is being trialed through the Organic Seed Partnership. The F1 generation produced a rather squat medium sized white pumpkin which a lot of folks like. This summer the seed from the F1 generation was planted and gave rise to a diverse tribe of interesting pumpkins that I posted pictures of in an earlier rambling. Now the pumpkins have been in the field all summer and we can take a closer look at them.
Below is Baby Boo, the male parent of the larger, slightly squat Ghost! F1. Ghost! is an easy to make your own hybrid pumpkin since both parents are readily available in commerce. It turns out that the F1 has very good baking qualities probably from Baby Boo, is a long keeper and has a better handle than Cotton Candy.
F1 Hybrids like Ghost! are not likely to be made by farmers because of the labor in hand crossing the two parents. To complete the breeding process and develop a stable open-pollinated variety you have to grow out the self of the F1 and then it becomes a selection process. It appears that a stable variety might be developed in just a few years. In 2007, the F2 generation was finally grown out and resulted in the following:
Most of the F2's have a round shape with a few plants producing the squat shape of the F1 (unlike Cotton Candy which is round to oval in shape). They have not yet matured (photo taken Aug. 1) so it remains to be seen whether the shade of white will remain bright or become more cream. There is indeed variation in the siblings and some developing fruit (not in photos) look promising also. It is interesting that some of the plants are quite vining like Baby Boo, others are more compact or upright.
The F2 generation of pumpkins from Cotton Candy x Baby Boo F1 (Ghost!) have been in the field exposed to the full sun and high temperatures past their ripening period. Ghost! was a flatter Cotton Candy type which retained it's bright color better in the field. What you can see in this photo is the variation in color after prolonged sun exposure (late October). Cotton Candy will typically turn a cream or yellow unless harvested early and protected from the sun and you can see that some of the F2's show this trait to an even greater degree. Baby Boo; however, remains white and you can see that some of the F2's show that characteristic as well. Then, there are some that have turned an uncharacteristic buff-pink color. I don't know where that came from. The F2 generation (Ghost! tribe) of the two "white" pepo pumpkin parents shows the degree of new genetic combinations one can expect as segregation of characters occurs.
It's by a simple "mixing it up" of the genetics to obtain some expression of the recessive traits that one can obtain a nice pool to select from. From this cross we may decide to select for a "Cotton Candy" type that retains it's bright white color or explore the stronger handles and longer keeping characteristics that we see in other siblings. The off-color pinks I will process the seed of but I suspect they won't find a place in my garden next year. But I will save the seed and maybe someday when I have time and space, I'll plant them out to take another look at them. The yellows I will probably heave onto the compost.
That is a problem that plant breeders wrestle with. You produce all this great variation but it's just impossible to explore every possibility that is offered by the cross and so much has to be tossed or shelved because of time limitations and the labor and other expenses of growing everything you might want to out. It's always a tough call to decide what it is you want to work with and what you will have to shelve and it is useful to have a clear breeding objective to focus on.
Some of the F2's were round, smooth and pure white. They also are surprisingly long keepers. We were putting up the holiday lights stumbling over the last of these little pumpkins and I began thinking why are pumpkins only a Halloween and Thanksgiving item. I would start them in late June to produce a late crop and then harvest them before frost in late October and then cure them in the dark until December. My little niece used a glue stick and some glitter to turn the smooth surface of some of these pumpkins into attractive Holiday decorations. The solid flesh can be sliced into pumpkin strips. Dipped into salad dressing, the kids thought they tasted "crunchy and pretty cool". Needs work to stabilize into a consistent variety. Maybe then it will extend the farmers season a bit as a cash crop- who knows?