Cotton is not only an important source of textile fibre and edible oil but also a valuable source of high-quality protein and fodder, because 45％—50％ of the cotton seed powder is protein. However, the cotton seed of cultivated cotton usually contains a special polyphenol compound called gossypol, which is poisonous and hinders the utilization of the seeds. Therefore breeding new cotton species with no or Cotton is not only an important source of textile fiber and edible oil but also a valuable source of high-quality protein and fodder, because 45% -50% of the cotton seed powder is protein. However, the cotton seed of cultivated cotton usually contains a special polyphenol compound called gossypol, which is poisonous and hinders the utilization of the seeds. Therefore breeding new cotton species with no or