Watermelon mixed seed project

I've recently acquired a batch of more than 200 watermelon seeds containing a mixture of unknown varieties, sizes, various flesh colors, etc.  I'm working through my plan for growing them out, and the theory that will be my "reasons" for keeping seed from the offspring.  Since I don't know exactly how old the seed is, I plan to do indoor germination on a heat mat to help things along when growing out this original seed.  It may take a few years to get through growing out all of this initial seed (if I can't borrow some growing space), but once that is done, the future generations will be direct sown for further natural culling.  So, the question is now, what to select for amongst all this variety?

-The germination process will cull the first round of weak seed, then plant health and vigor will be the next determining factor in selection.
-Flesh color doesn't matter to me in this batch of seed, because I'm actually curious what the various crosses will produce (red, pink, yellow, pale yellow, white, orange).
-Melon size isn't very important to me at this stage, but overall productivity is.  I'm thinking more melons per vine equates to easier pollinating varieties, which is a positive genetic trait to me.
-Rind color doesn't matter to me.
-Good watermelon flavor must be there to stay in the mix, not only sweetness.

-Because of the variability of these results, this is intended to be a fun project/ personal-use locally adapted variety.  I'm thinking after many generations of selection for my desired traits, within the constraints of my landscape, I should arrive at a near maintenance-free, very sweet, direct-sown, disease and pest resistant watermelon...at least that's the best case scenario.  Worst case, I taste test all the watermelon I can stand, which is still a good outcome.

Does anyone see anything else I'm missing with regard to choosing my future seed?  

Am I correct in my understanding that all seeds within a melon will be fertilized from a single male flower (meaning I don't have to keep every seed from each good melon), or can they be fertilized by multiple pollen grains/male flowers from different plants?  I mean since it's not like corn that can have pollen from a hundred male plants fertilize the ear?  I know that bees or other pollinators will carry pollen from multiple donors, but is it necessary to keep all of the seeds from the melon because they may contain different fathers/genetic material?  

I don't know anything about watermelon pollination but it sounds like a fun experiment.  Where did you get such a wide mix of seeds?

In my experience, my watermelon seed germination rate drops a lot after the first year which makes it hard for me to save seeds since in my climate I don't always get ripe fruit, let alone viable seeds every year. I'll enjoy seeing what happens with your experiment since it's not really one I can do myself!

Every seed in a fruit has the same mother.
Every seed in a fruit might have a different pollen donor.

I find that the ecosystem does 80% of the selection.

Watermelons are my weakness. Any time I look at seed catalogs with them, I think "gotta try them all!" and then have the hardest time narrowing them down. Your experiment would be a dream come true for me.

Other factors you may want to choose seed for:
-- Thickness of rind - there are pros and cons to thick vs thin.
-- Earliest producers
-- Vigor of plant and production during extreme weather - cool, hot, dry, sopping wet

Since you want to ultimately direct sow, if I had this opportunity, I would consider winter sowing (planting the seeds in clear jugs or bottles outside, frequently before the last frost. They sprout when temperatures are right). The jugs protect the seeds from insects and critters but aren't fully coddled. It could give you a head start on seeing which seeds are suited best for your weather.

Is there any reason you won't be trying to select for ease-of-growth?
Personally, I would direct sow and see what happens. Those plants that survive and produce fruit by the time frost hits are winners, and require much less babying and work on your side.

I'm gardening in a new region this year and have direct sown most of my melons (testing 5 varieties) to see what happens. So far the direct sown melons are doing a lot better than the transplanted starts, despite several weeks of a head start.

I like a melon that is tasty without being too sweet and holds plenty of water. We make a nice watermelon drink here, blend it with ice and maybe a bit a sugar, or lemon, or even sun tea depending on your taste and enjoy on a hot day.

Jenny
- I bought the seeds from Amazon.  It was a lot of 200 for about $10, so not much invested in this gamble.  The couple reviews weren't great, but to me that wasn't enough to deter me.  I figure if I germinate them on a heat mat & grow light setup a month or so before planting, I'll have the best shot at germinating.  

Joseph
- Thanks.  I wasn't 100% sure, but thought I'd ask.  I've learned from my sweet corn projects, that there is a lot of seed produced and only so much can be planted.  I've read various studies about trait dominance in watermelons, and for the most part, lighter flesh is dominant over darker flesh, darker rind over lighter rind, & darker seeds over lighter seeds.  Of course there exceptions, and certain things affect other things, but in this batch, I'm not really interested in exact science, only good growing, good tasting, good producing watermelons.  I recall reading somewhere that you had a landrace watermelon project at one time, but I don't remember how it turned out.  I'm not in an extreme micro-climate, so my selection will firstly be environmental, then based on personal taste really.  In your mixture of varieties, did you notice a dominant type or flesh color over time, or was it always a random surprise when you cut into the melon?

Nikki
- I know what you mean!  I'm that way with Sweet corn, Watermelon, and cantaloupes.  I suppose I just love full flavored sweet fruits.  Thanks for the ideas, I did consider rind thickness, but then I thought about "What do I actually like in a melon when I cut into it?"  I know that thicker rinds are better for transporting them to market, but my personal needs don't require that.  I know when I cut into a cantaloupe for example, I'm impressed then the edible (palatable) meat of the melon gets as close to the rind as possible, giving me more melon to eat.  On the other hand, perhaps a thicker rind will help prevent bug damage, and offer a longer storage life?  If that's the case, a thicker rind would definitely be worthwhile.  My original thought was "As long as they don't explode, I'm good with it."  Now I think I've decided to look for a suitably thick rind!  
- I'll add "early producers" to my selection influence, that way when I begin direct seeding at the right soil temps, I will actually get mature melons in time.
- I grouped the plant vigor & harsh weather conditions under "plant health & vigor", which will be the 2nd natural/personal culling/selection criteria after germination.

Simon
-While these seeds were well cleaned and sealed in an air tight plastic bag, I don't know the exact age of this seed, or the temperature it was stored in.  I'm planning to give the seeds their best shot at germinating under ideal conditions to start with the most genetic material in this 1st generation.  I suspect I'll have a fair number of seeds that will fail to germinate, so I am planning to start more than I need to grow so that I have sufficient transplants to start next season.
-"Ease of growth" is definitely a consideration, but will occur in the "direct sown" 2nd generation since I'll know the age of the seed, the conditions it was stored in, and have selected traits from the first generation to gradually "steer" toward what I want to produce, or away from what I don't.  In the end, I'd like to plant seed before a rain and let it go until harvest.  I'm currently growing 20 watermelon plants that were direct sown, and do prefer this method.  I'm just trying to capture the most from the 1st generation seed.

Melissa
-I always enjoy the first smell and the first bite of a freshly cut into melon of any variety.  I will have one of three thoughts after that; Wow, that's a good melon, it's average, or it's underwhelming.  I am targeting the first one as often as I can.  I will have to look into more ways to enjoy watermelons like drinks and tea.  As it stands, I eat about one melon of some variety every other week throughout the summer.  Aside from simply enjoying them as-is, I'm also gaining an education on what I do or don't like in a melon.  It's an evolution of understanding of sorts.  Thanks for the inspiration.

Note: I bought these seeds out of curiosity to see what I could get out of them.  It was the most genetic material in the lot size I wanted to experiment with.  The unknown varieties keep me honest in selecting for traits rather than trying to fit my expectations to known types.  If I ever wanted to add known types, I can, but I just wanted to see where this material gets me first.  If this doesn't work out, I'm not out much, but if it does, I'll have learned something useful to me.