Waterlogging events during stem elongation or flowering affect yield of oilseed rape (Brassica napus L.) but not seed quality

Oilseed rape suffers from serious waterlogging in many regions of the world limiting the cultivation area for rapeseed. Due to the man-induced climate change, the risk of severe waterlogging events and associated therewith the damage of rapeseed plants will increase, even in Europe and North America. To investigate the effects of waterlogging on growth, yield and seed quality, rapeseed was cultivated throughout its vegetation period and waterlogged for 14days at two different growth stages: at stem elongation (BBCH 31) or at floral bud appearance (BBCH 55). The experiments revealed that waterlogging at BBCH 31 affected plant growth and nutrient accumulation and finally resulted in lower yields. Waterlogging at BBCH 55 seriously impaired main racemes, but due to an increased production of secondary racemes, yield losses were lower than after waterlogging at BBCH 31. Oil quality was not affected by any waterlogging treatment under the chosen experimental conditions.