MARKER ASSISTED INTROGRESSION OF THE APETALOUS CHARACTER INTO OILSEED RAPE (Brassica napus L.)

¹ Brassica and Oilseed Research Department, John Innes Centre, Norwich Research Park, Colney Lane, Norwich. NR4 7UH UK

² Department of Agriculture, University of Newcastle Upon Tyne, Newcastle Upon Tyne. NE1 7RU UK

³ CPB Twyford Limited, Church Street, Thriplow, Nr Royston, Herts. SG8 7RE UK

⁴ Molecular Genetics Section, Saskatoon Research Centre, 107 Science Place, Saskatoon, Saskatchewan. Canada S7N 0X2

The floral canopy of oilseed rape compromises the yeild potential of the crop as the transmission of the photosynthetically active radiation (PAR) to the leaf canopy is significantly reduced during anthesis. Recent studies have determined that the petals absorb 64% and reflect 14% of the PAR (Fray et al., J. Agr. Sci. 127:193-200). Rao et al. (1991, J. Agr. Sci. 117:189-196) proposed a strategy to improve the photosynthetic efficiency of the crop by utilising an apetalous variant of Brassica napus. It was suggested that the generation of an apetalous variety of oilseed rape may return a greater yield than petalled varieties without an increase in agricultural costs. This study details the production of apetalous near isogenic lines using the apetalous variant N-o-112 and the commercial cultivar Tapidor as the parental material. The apetalous character from N-o-112 is controlled by two major loci and a third modifying locus (Fray et al., 1996, J. Agr. Sci. 127:193-200). These three loci have been mapped to the linkage groups N8, N15 and N12 respectively. The Apet alleles have been introgressed into a Tapidor genetic background using marker assisted backcrossing to create apetalous near isogenic lines. The effects of the apetalous character will be determined using field trilas during the 1998-9 growing season. Populations have been developed to fine map the three Apet loci utilising the synteny between Brassica and Arabidopsis enabling more efficient introgression of this trait by reducing linkage drag.