Oilseed rape hybrids

Halfhill, M.D., R.J. Millwood, P.L.Raymer, and C.N. Stewart, Jr. 2002. Bt-transgenic oilseed rape hybridization with its weedy relative, Brassica rapa. Environ. Biosafety Res. 1 19-28. 

McVetty, P.B.E., Edie, S.A., Scarth, R., 1990. Comparison of the effed of andpo/cytoplasms on the performance of intercultivar summer oilseed rape hybrids. Can. J. Plant Sd. 70,117-126. 

Grant, I. and W.D. Beversdorf (1985). Agronomic performance of triazine-resistant single-cross hybrid oilseed rape (Brassica napus L.). Can. J. Plant Sci., 65 889-892. 

Brandle, J.E., and P.B.E. McVetty. 1989. Heterosis and combining ability in hybrids derived from oilseed rape cultivars and inbred lines. Crop Science 29 1191-1195. 

Franen, M., and W. Paulmann. 1999. Breeding of hybrids varieties of winter oilseed rape based on the MSL-system. Tenth International Rapeseed Congress, Canberra, Australia, pp. 258-263. 

Thompson, K.F. 1972. Cytoplasmic male sterility in oilseed rape. Heredity 29 253-257. Thomas, P. 1992. Canola Growers Manual. Winnipeg, Canada Canola Council of Canada. Vincent, M.R.L. 2008. Genetic diversity and its relationship to hybrid performance in high eructic acid rapeseed. M. Sc. Theseis. University of Manitoba, Winnipeg, Manitoba, Canada. 

Table 1. Comparative agronomic performance of triazine tolerant and susceptible cytoplasms in identical nuclear backgrounds (reciprocal single cross hybrids) of oilseed rape...

Combination of atrazine resistance and cytoplasmic male sterility in rapeseed. Transfer of atrazine resistant chloroplasts from bird s rape (B. oapestris) into oilseed rape has been accomplished by back-crossTng (s this volume). The purpose achieved by somatic cell fusion was to combine the atrazine-resistant chloroplasts carried by a B. napus line with cytoplasmic male sterility (CMS), a mitoohondrlal tralt (l9). The CMS trait was carried by a B. napus line with the cytoplasm of radish (Raphanus sativus). Since both traits, atrazine resistance and CMS, are maternally inherited in sexual crosses, the only way to combine the traits was by protoplast fusion. The desired atrazine-resistant cybrids were identified in a randomly regenerated sample of plants by the presence of the CMS flower morphology and their darker green color at low temperature. Somatic hybrids rather than cybrids were obtained in each clone since no irradiation had been used to facilitate the elimination of one of the parental nuclei. 

Oilseed rape has received most attention regarding l bridisation in recent years. In 2012 about half of the NIAB recommended and provisionally recoimnended varieties were hybrids and many showed yield advantages or other desirable traits compared with conventional varieties. These restored hybrids are FI hybrids produced in a variety of ways, usually from crossing inbred lines but sometimes from more complex breeding operations involving open pollinated varieties. 

Oilseed rape and tnmip rape are 60-70% self-fertile bnt they will also ont-cross readily with other species, if in flower, such as swedes, fodder tnmips, fodder rape, black and brown mustards and Chinese cabbage. Volunteer oilseed rape plants in neighbouring fields can be an important source of pollen contamination (especially the high emcic acid varieties). Isolation requirements for seed crops are therefore quite stringent. There should be a physical barrier or at least 2 m fallow between the crop and aity other crop likely to cause contamination. In addition, there should be an isolation gap of at least 200 m between a certified seed crop and aity source of pollen contamination such as other varieties of oilseed rape or any of the crops mentioned above. For the production of Basic seed this minimum isolation gap should be doubled to 400 m and for hybrid varieties these distances must be increased by a further 100 m. 

---