Pollination Performance and Agronomic Value of Three Managed Pollination Systems in Hybrid Oilseed Rape Seed Production Under Cage Conditions

Due to the increasing demand for rapeseed oil for food and industrial applications, the development of hybrid cultivars with higher seed and oil yields has recently become increasingly important. An assessment of the efficacy of different pollinator species and their effects on yield and seed quality is critical for improving hybrid seed production and ensuring sustainable crop performance. The aim of this study was to evaluate the pollination efficiency of different pollinator species in hybrid oilseed rape under semi‐controlled conditions using isolation cages. Three Hymenoptera species were used for the experiment: the buff‐tailed bumblebee— Bombus terrestris (Linnaeus, 1758), the European orchard bee— Osmia cornuta (Latreille, 1805) and the red mason bee— Osmia bicornis (Linnaeus, 1758). These species were evaluated as managed pollination systems, as the treatments differed not only in pollinator species but also in their management approach, with a commercial bumblebee colony used for B. terrestris and a fixed number of individuals introduced for each Osmia species. Their impact on key agronomic traits, including the number of pods per plant (NPP), filled and unfilled seeds per plant (FS and UfS), proportion of unfilled seeds per plant (UfS_pct), filled seeds per pod (FSP), seed yield per 100 pods (SYP100), total seed yield per plant (TSYP), thousand‐seed weight (TSW), test weight (TW) and oil content, was evaluated. The results showed that all pollinator treatments significantly increased NPP, FS and FSP compared with the control. Significant increases in SYP100 and TSYP were treatment‐dependent, with O. bicornis significantly increasing both parameters and B. terrestris significantly increasing TSYP, while increases observed with O. cornuta were not statistically significant. Oil content was significantly lower in the control than in the treatments with O. cornuta and B. terrestris ; however, the increase observed with O. bicornis did not reach statistical significance. For most parameters, no significant differences were detected among the three pollinator treatments.