Compatibility between cytoplasm and a single chromosome derived from Diplotaxis tenuifolia results in selectable female sterility in Brassica rapa
Yoshiaki Fujita
Utsunomiya University, Japan
Tokyo University of Agriculture and Technology, Japan
: J Plant Physiol Pathol
Abstract
In plants, particular combinations between nuclear genomes and alien organelle genomes often results in Cytoplasmic Male Sterility (CMS). Diplotaxis tenuifolia (Dt) used as a cytoplasmic resource belongs to Brassiceaceae and is a wild plant closely related to Brassica crops. We have tried to produce a B. rapa CMS line (2n=20) carrying D. tenuifolia cytoplasm (cyt-Dt) by means of an intergeneric crossing between D. tenuifolia and B. rapa and successive backcrossing with B. rapa. However, the alloplasmic B. rapa line has not been obtained through the breeding work of several years and only a type of Monosomic Addition Line (MAL) has been produces. Here, we investigated female fertility and embryogenesis in the (cyt-Dt) B. rapa MAL. The pollen tube attraction rate at the micropyle of the ovule of the (cyt-Dt) B. rapa MAL was approximately 50% compared with the autoplasmic B. rapa line. Most of fertilized embryos of the (cyt-Dt) B. rapa MAL reached the mature stage in an enlarged ovule at thirty days after pollination. It was suggested that the ovules without alien additional single chromosome may fail to develop female gametophytes and that the pollen tubes could not be attracted. It is possible that only the ovules with alien additional single chromosome could produce monosomic addition progenies. These results suggest that the female gametes of n=10 and 11 were developed in the (cyt-Dt) B. rapa MAL. When it was crossed with B. rapa lines only the female gametes with n=11 were fertilized and developed mature seed. It might be the reason why all progenies were obtained as MAL.
Biography
Yoshiaki Fujita is currently a PhD student of Tokyo University of Agriculture and Technology in Japan.
E-mail: orange_yoshi_18@yahoo.co.jp
