The effect of waterlogging on yield and seed quality at the early flowering stage in Brassica napus L.

Rapeseed (Brassica napus L.) suffers from serious waterlogging stress due to the rapeseed-rice rotation system and heavy precipitation in China, which contains the largest rapeseed planting area worldwide. A field experiment was conducted using 20 rapeseed varieties to evaluate the effect of waterlogging at the early flowering stage on yield and seed quality. The results showed that waterlogging stress affected rapeseed growth and caused yield loss. Except for branch height (Bh) and thousand seed weight (Tsw), all other traits were significantly affected by waterlogging. A correlation analysis revealed that the waterlogging tolerance coefficients (WTCs) of all the morphological traits were significantly correlated with that of yield, except of the WTCs of Bh and branch number (Bn). However, the WTCs of seed weight and seeds per silique were not found to be significantly correlated with that of yield. The assessments of yield-related traits revealed that the reduction in the number of siliques per plant after waterlogging is mostly due to the decrease of siliques on branches, which governed the final yield after waterlogging. Additionally, waterlogging affected the oil quality by increasing erucic acid (C22:1) and glucosinolate content. Waterlogging also caused an increase in linolenic acid (C18:3) and a decrease in linoleic acid (C18:2), indicating that waterlogging might affect metabolic pathways involving lipid biosynthesis. Our study reveals the effects of waterlogging on different varieties of rapeseed at the early flowering stage and provides some data that may be useful for breeding more tolerant varieties. (C) 2015 Elsevier B.V. All rights reserved.