Genetically Modified Food - good case studies

Have scientists created good plants that will enable food production in developing countries where the problem is water?
They are doing their best while results are "somehow" promising.

How far can GM food go?
When combining genes from plants and animals things get strange but resulting organisms may have good characteristics from both sides..

Combining genes from plant and fish result in new gene.

What about natural selection?
Yes, natural selection can be controled artificially. If you only use seeds from plants with best performance there are good chances that good results will occur next season. But genetic modification can be even more effectively.

What are good case studies of GM food?
Good case studies are soybeans, where herbicide resistance gene was inserted from bacteria. Most worldwide soyabeans are now resistant to some herbicides. Another example is M37W corn that beside being resistant to herbicides additionally contain 6 times more C vitamin due to genetic modification.