The effects of winter waterlogging and summer drought on the growth and yield of winter wheat (Triticum aestivum L.)

Winter waterlogging and summer drought may become more prevalent as a result of climate change. Their effects on the growth and yield of winter wheat were investigated. Wheat was grown in lysimeters in an unheated glasshouse, over two seasons. Seed rate was included as an additional factor in the first season, and cultivar in the second. Root growth was investigated in both seasons using mini-rhizotrons. Waterlogging for 44 days at 93 days after sowing in 2002, and 58 days at 64 days after sowing in 2003, decreased grain yield by 20% and 24%, respectively. Drought during grain filling further decreased yields but there was no evidence that winter waterlogged plants were more susceptible to damage from drought the following summer, the effects of the two stresses being additive. Waterlogging decreased the total length, but not the final depth of the root system. Plots with a lower plant density demonstrated a smaller decrease in yield due to waterlogging. There was a significant positive linear relationship between the number of shoots per plant and nodal root axes per plant. There appeared to be a difference between cultivars in root system architecture, and in their response to waterlogging, but these differences were not reflected in grain yield.