Grain yield of durum wheat as affected by waterlogging at tillering

Waterlogging is one of the limiting factors influencing durum wheat (Triticum durum L.)\udproduction. In this paper we investigated the impact of seven waterlogging durations of 4, 8,\ud12, 16, 20, 40, and 60 days, imposed at 3-leaf and 4-leaf growth stages, on grain yield, grain\udyield components, straw and root dry weight and nitrogen concentration of grain, straw, and\udroots of two varieties of durum wheat. Grain yield of both varieties showed a significant\udreduction only when waterlogging was prolonged to more than 20 days, and 40 and 60-d\udwaterlogging reduced grain yield by 19% and 30%. Waterlogging depressed grain yield\udpreventing many culms from producing spikes. It slowed down spikelet formation, consequently\udreducing the number of spikelets per spike, and reduced floret formation per spikelet,\udthus reducing the number of kernels per spike