I have a State Water heater (50 gal. propane ) two years old. The pilot light went out this morning. When I light the pilot and hold it for one minute and release it goes out, and will not stay on.

You have a defective thermocoupling. Thermocoupling is that probe the is in the pilot light flame and has a wire to the gas valve. Heating the probe sends a small electrical charge to the gas valve, telling the gas valve that the pilot light is burning. Thermocouplings are available at Home Depot and Lowe's and are easily replaced.