Abstract: The Ogura CMS lines of Chinese cabbage—pak．choi f Br~sica campestris L．ssp．chinensis
Makino var．cornmunis Tsen et Lee．)and turnip[B．campestris L．ssp．rap r(z(Metzg．)Sinsk]were ob．
tained through interspeeifie hybridization between Ogura CMS in B． nap us and Chinese cabbage．pak．choi and
turnip，and successive backcrosses with Chinese cabbage—pak—choi and turnip as male parents． namely ‘Xin．
xuan Ogu28-4’， ‘Aijiaohuang Ogu33—14’， ‘Naibing Ogu18-4’．Cytomorphological studies indicated that
the inhibition of Ogura CMS B．campestris anther development may occur at the tetrad．uninucleic pollen stage．
The microspores stop developing at the uninucleic stage， quickly degenerated to disappear， and abort
absolutely before blossom． Tapetum of the male sterile line began vascuolation during meiosis and did n0t
disappear even when the uninucleic microspores had degenerated while that of the male fenile line began to
generate at tetrad stage and disappear after the pollens had matured． The different nuclear background 0f
Ogura CMS lines had similar abortive character．It might indicate that the relation of nueleo．cvt0plasmic inter
action iS steady，and the cytoplasmic effects were hardly affected by the nucleus of the sterile】ines．

Key words: Brassica campestris ssp．chinensis, Brassica campestris ssp． rap r(z, Brassifa rap0：Chi—nese cabbage’pak—choi, Turnip, Ogura CMS, Microsporogenesis, Cytomorphology