Abortive process of a novel rapeseed CMS line derived from somatic hybrids between Brassica napus and Sinapis alba
Juan Wang¹, Jinjin Jiang¹, Aimin Li², Yongtai Zhang², Youping Wang^1*

¹ College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009.
² Jiangsu Institute of Agricultural Science in the Lixiahe District, Yangzhou 225009.
^*Corresponding Author：Tel: (+86514) 87997303; Fax: (+86514)87991747; E-mail:wangyp@yzu.edu.cn

Abstract
Somatic hybridization is performed to obtain significant cytoplasmic male sterility (CMS) lines, which are derived from the transfer of sterile genes that are rooted in the mitochondria from the donor parent to the receptor or in the production of new sterile gene caused by mitochondrial genome recombination from the biparent during protoplast fusion. A novel male sterile line, SaNa-1A, was identified from the somatic hybridization between Brassica napus and Sinapis alba. In this study, we described the normal anther development of maintainer line, SaNa-1B, and the abortive process of SaNa-1A through phenotypic observations and microtome sections. The floral organ of the sterile line appears fertile one with a shortened filament and a deflated anther. No detectable pollen was attached to the surface of sterile anthers. Semi-thin sections indicated that SaNa-1A aborted in the pollen mother cell (PMC) stage, in which tapetum and pollen mother cells began to show vacuolization. The tapetum radially elongated and became highly vacuolated, which, occupied the entire locule with vacuolated microspores.

Keywords: Brassica napus; somatic hybridization; cytoplasmic male sterility (CMS); anther abortion; semi-thin sections