What is the difference between traditional plant breeding and the creation of genetically modified organisms?

What is the difference between traditional plant breeding and the creation of genetically modified organisms? What is a transgenic organism? Come up with s transgenic organism that solves a real-world problem (for instance, splicing mangrove DNA into tomato plants so that they can grow in salty soil or splicing human DNA into a cow so it can produce human breast milk). Are there any ethical, environmental, or social concerns with your creature? Should we build your organism? Why or why not?