Greetings, I would like to thank you for your question. It seems from your question, you ask about wheat growth under in vitro condition. If so, the best explant used is embryo especially immature better than mature after 10 -14 days (2-4 mm) under microscope you could get the embryo. The best media is MS media with some modified.
Dear Maria, Khaled is right, the embryo if a good source. You can try Gamborg B5 as well, and you can buy it readily mixed at Duchefa (Netherlands) or Sigma (Germany)?! The seeds can be sterilized by commercial bleaches (NaOCl?!) Natriumhypochlorite as well. For exact data please browse publications which describe the maize wheat doubled haploid procedure in combination with embryo rescue technology. 70% Ethanol should work as well, but I provide no guarantee on survival rates....maybe you test different concentrations and treatments durations as well. Best wishes Jens