What characteristics are manipulated in watermelons?

Watermelons have two parts: fruit and plant. Each part has different traits that have been modified according to growers and/or consumer preferences for flavor, appearance, resistance to disease, increased storage time and better shipping properties. Each of the described traits can be introduced into a particular plant or fruit depending on consumer demand, environmental requirements and grower needs. The process of trait modification is labor intensive and may require more than ten years of development to produce inbred plants that consistently demonstrate the desired characteristics. One of the problems that keeps plant breeders from using the modern tools of genetic engineering is the fact that there are a limited number of vectors available to manipulate plant genetic material. Additionally, the location of many of the genes specifying certain plant or fruit traits is not yet known.

The fruit has the following traits, many of which are influenced by consumer preferences rather than conferring any biological advantage:

1. flesh color that can be red, pink, yellow, orange, cream and white
2. flesh texture from soft to tough
   
3. rind that is thin or thick
   
4. sharp boundaries between flesh and rind (demarcation line)
   
5. enhanced storability
   
6. flesh taste from bitter to sweet
   
7. rind resilience to cracking or breaking
   
8. rind resistance to sun scalding
   
9. rind color that is gray(light gray-green), dark green, dark green with light colored stripes, gray with stripes
   
10. shape that is round, oval or long
    
11. size that varies from 0.5 lb to 220 pounds.
    
12. seeds that are small, medium or large ranging from as few as 3,000 seeds to more than 30,000 seeds per pound
    
13. seeds that are tender enough to eat to those that are woody and tough