Monday, March 4, 2013

Seedless Watermelon

 How do plant breeders obtain seed for a seedless watermelon?

 This is accomplished by making several different types of crosses between watermelon plants. Without going into a long genetic lesson, it first begins by doubling the number of chromosomes  (threadlike bodies in cells that contain  genetic information) in a normal watermelon plant.  This is done by chemical treatment. This new plant is referred to as a tetraploid because it now contains four sets of chromosomes instead of the normal two.  When the tetraploid plant is bred back, or pollinated, by a diploid plant, the resulting seed produces a plant that is basically a "mule" of the plant kingdom – one that produces seedless watermelons. The flesh of this melon is usually firmer than seeded varieties, because the usual softening of the fruit around the seeds does not occur.