Cytoplasm of CMS line influence the expression of F_1 of hybrid rice.The effect of a certain CMS cytoplasm on different characters of F_1 is dissimilar and different CMS cytoplasms have vary effects on a same character.Most of CMS cytoplasms present negative effects.A practical method to reduce or eliminate the negative effects of CMS cytoplasm is selecting elite CMS cytoplasm or strong restorer by broadening CMS cytoplasm base.It is necessary to breed homokaryon-alloplasm sterile line with multiple cytoplasms for hybrid rice production.