A lot of interesting informations:
http://www.google.sk/url?sa=t&rct=j&q=Citrus.+Genetics%2C+Breeding+and+Biotechnology%2C+2007%2C+p.381.pdf&source=web&cd=1&ved=0CC0QFjAA&url=http%3A%2F%2Fbiology.krc.karelia.ru%3A8080%2Fbiology%2F%25D0%2593%25D0%25B5%25D0%25BD%25D0%25B5%25D1%2582%25D0%25B8%25D0%25BA%25D0%25B0%2F%25D0%259D%25D0%25B0%2520%25D0%25B0%25D0%25BD%25D0%25B3%25D0%25BB%25D0%25B8%25D0%25B9%25D1%2581%25D0%25BA%25D0%25BE%25D0%25BC%2520%25D1%258F%25D0%25B7%25D1%258B%25D0%25BA%25D0%25B5%2FCitrus.%2520Genetics%2C%2520Breeding%2520and%2520Biotechnology%2C%25202007%2C%2520p.381.pdf&ei=w-_8UMfaA-iF4AT47IDABg&usg=AFQjCNHFgVOsR_uAZigyZr-MEFruuJjeKA&cad=rja