OUTCROSSING IN RAPE AND MUSTARD UNDER SASKATCHEWAN PRAIRIE CONDITIONS

The interplant outcrossing rate was studied for one cultivar and four lines of rape (Brassica napus) and three cultivars of mustard (Brassica juncea) under field conditions at Saskatoon, Saskatchewan, in 1982, 1983 and 1984. Marker characters used for determining outcrossing rates were seed oil erucic acid content for rape and seed color for mustard. The average interplant outcrossing rate was 21.8% for rape and 18.7% for mustard. No significant differences in outcrossing rates among the one cultivar and the four lines of rape or the three cultivars of mustard were detected. A wide range in outcrossing rates between plants within cultivars and lines was observed for both species, but whether this variation was genetic or was environmentally induced could not be determined in these experiments. Some of the implications of this partial outcrossing on methods used for the breeding of these crops are discussed.