Flower morphology and pollination features of winter and spring rapeseed varieties bred at V.S. Pustovoit All-Russian Research of Oil Crops

To evaluate the similarities and differences in the reproductive mechanisms of winter and spring rapeseed in the south of Russia, we studied the characteristics of the bud, flower, and its elements; the potential productivity of the reproductive organs; and how this potential is realized in various pollination variants. From 2020 to 2024, the study was conducted in the central zone of the Krasnodar region using commercial varieties of winter and spring rapeseed bred at V. S. Pustovoit All-Russian Research Institute of Oil Crops (VNIIMK). Winter rapeseed varieties significantly exceeded spring rapeseed varieties in bud and flower size. Differences were observed in both the length (1.5 mm) and width (0.5 mm) of buds in the fourth stage of development. Winter rapeseed plants had higher flower diameter (by 6.2 mm), corolla petal length and width (by 2.3 and 3.2 mm, respectively), and were characterized by longer stamen filaments (by 1.2 mm), anthers (by 1.1 mm), styles with stigmas (by 0.3 mm), and ovaries (by 1.3 mm). The average potential productivity of winter rapeseed plants reproductive organs did not differ significantly from that of spring rapeseed plants. The average number of ovules in the ovary of a flower was 31.7 in commercial winter rapeseed varieties and 30.6 in spring rapeseed varieties. Winter and spring rapeseed varieties are equally prone to self-fertility. Thus, the percentage of seeds set within a single flower was 52.3% and 52.4%, respectively. Winter rapeseed set 61.0% of seeds when pollinated within a single plant, while spring rapeseed set 66.1%. Winter rapeseed varieties readily accepted pollen from other plants of their own variety – 64.5%. The same tendency was observed in spring rapeseed varieties at 62.2%. With free pollination, the average seed set was 78.7% for winter rapeseed varieties and 76.1% for spring rapeseed varieties.