The genetics of melons is more complicated than you were told about in biology class.

In basic biology they discuss diploid genetics: two sets of chromosomes coming together. But melons come in triploid (three chromosomes) and tetraploid (four chromosomes) varieties as well, even within the same species of melon.

Most melons are grown as hybrids: they mix two different species together to make the plants. Those plants don't breed true. That is, if you plant the seeds you grow, they won't turn into the same plant, because the complex genetics mix differently. Using hybrids of two other species gives consistent results.

Some melons are deliberately crossed to produce seeds that don't develop. That's how you get seedless melons. You can get more of them by breeding the parent species again, but they don't grow themselves. Those tend to be the ones where they mixed a diploid with a tetraploid species, yielding a triploid that doesn't develop seeds.

When you see a plant with one seed different from the others, you're often looking at a case where the chromosome count matched up differently. That happens when the chromosomes divide and mix in producing the seeds and pollen. Thus, you can get a dark seed in a plant otherwise producing light ones, or a seed in a seedless melon.
Source(s):
http://edis.ifas.ufl.edu/CV006

Asker's Rating:

Permalink | Report