Abstract:Cytoplasmic malesterile (CMS) lines, especially K (Aegilops kotchyi), V (Aegilops ventricosa), and T (Triticum timopheevii) types of cytoplasm, are of high value in heterosis utilization in wheat (Triticum aestivum L.). The aim of this study was to discuss the relationship between CMS and chloroplast and to reveal the mechanism of CMS by investigating chloroplast DNA and RuBP carboxylase (rubisco) activity in CMS malesterile lines. The experiment was conducted with cultivars of the K, V, Ttype CMS lines, the common maintainer ‘Tai 911289’ and ‘Ji 5418’, the F1 hybrids and the cytoplasmic donors under field conditions. The major results are as follows: (1) the polymorphism between male sterile lines and maintainer lines in cpDNA, and specific fragment in the different cytoplasm type male sterile lines provides evidence of three types of cytoplasm male sterile lines from different sources, and found 5 specific primers and 7 specific primers respectively to identify V and T type sterile lines. (2) There is no difference in cpDNA between the male sterile lines and their cytoplasm donors, except K‘ji5418’, and because of its nature of maternal inheritance also showed no polymorphism in cpSSR amplified fragment between the male sterile lines and its fertility restoration in the F1 generation. (3) RuBP carboxylase activity of two sets of male sterile lines was significantly higher than that of maintainer lines. In the F1 generation, with the recovery of fertility restorer, its RuBP carboxylase activity is higher than that of maintainer lines, but lower than the respective male sterile lines in standing and flowering period. However, there is no difference between them in jointing stage.