DEVELOPMENT AND REPRODUCTIVE BIOLOGY Molecular evidence of outcrossing rate variability in Brassica napus

Introduction Assessment of the mating system of a crop is particularly important for the design of adequate breeding and genetic conservation programs. Genetic inbreeding and heterosis, important factors that affect the production of the crop, are related to the mating system. Brassica napus L. includes economically important crops, such as oilseed rape, rutabaga and leaf rape. B. napus is considered as an autogamous species, although in field conditions it has a variable outcrossing rate, between 20 and 40% (Becker et al., 1992; Damgaard and Loeschcke, 1994). These estimates had been based on morphological traits or isoenzyme analysis. At present, accurate estimates of outcrossing rates can be obtained using multilocus approaches. Also the estimates of outcrossing rates in the field are subjected to environmental variation. The objective of this work is to study the outcrossing rate in Brassica napus L. cultivated under controlled conditions using a SSR multilocus approach.