There are not F1 hybrids because of no good male sterile materials or self incompatible lines in Brassica campestris L. ssp chinensis (L. ) Makino var. utilis Tsen et Lee. In this experiment, in accordance with the conservative region of DAD1 gene in Arabidopsis thaliana and B. campestris, the primer was designed
to amplify the DAD1 gene conservative region fragment (DAD1F) of B. campestris L. ssp chinensis var. utilis. Using this fragment to construct a antisense exp ression vector to develop adjustable male sterile plants. All
opend flowerswere removed from the inflorescence, and the remaining flowers were dipped into 500μmol·L -1 MeJA (Wako Pure chemical, Osaka, Japan) dissolved in 0105% aqueous Tween 20. The fragment amplified from B. campestris L. ssp ch inensis var. utilis was named as B rcpDAD1F. The homologous rates were 88% and 99% with that in A rabidopsis and B. cam pestris, respectively. The antisense DAD1F from B.campestris L. ssp ch inensis var. utilis, was connected to p lant exp ression vector pB I121. Using cotyledons with petiole as exp lants, Agrobacterium tum efaciens mediate transformation was performed with antisense BrcpDAD1F vector (pBI-antiBrcpDAD1F ) into B. campestris L. ssp chinensis var. utilis. The results of Southern bloting showed that antisense DAD1F had been transferred into B. campestris L. ssp chinensis var. utilis Tsen et Lee. Twelve transformantswere obtained, ofwhich 6 the mRNA of DAD1 were inhibited and disp layed male sterile, pollen germination percent of transgenic plantswere very low, which were not than 10%. After flowering, transgenic plants could not set or the siliquas were emp ty. Occasionally we could obtain seeds, but the seeds could not germinate. Pollinated with wild type plant pollen, the siliquas of transformed plants were enlarged and the seeds could be produced. No obvious differences were observed in morphology between transformed plants and wild type plants. A few flowers in transformed plants were abnormal. The pollen treated with 500μmol·L - 1MeJA could germinate in the medium and could fertilize. The fertile and sterile plantswere in the ratio of 3 to 1 in T1 population, 3 to 1 in some lines, full fertile in some lines full sterile in other lines in T2 populations. It suggested that antisense RNA can inherit inMendelmodel.
