Were do seeds for a seedless watermelon come from?

Will these sunflower seeds grow and produce more seeds?

• Last year I got a pack of Giant Hybrid Sunflower seeds. They were huge, like 10 ft tall and the heads were like 2 feet in diameter. So I got a bunch more seed than I anticipated. I roasted some of them but not all of them. I was wondering if the seeds that I did not roast would grow. I know that most seeds of hybrid plants wont produce more seeds unless there is a regular type of the same species there to pollinate it. Almost like seedless watermelons, they wont grow fruit unless there is a seeded watermelon there to pollinate the flowers, therefore creating seedless fruit. Does this apply to the hybrid sunflower seeds?

• Answer:

  Go ahead and plant them as soon as the weather warms up then go ahead and plant them. See what you get.