Grain yield of durum wheat as affected by waterlogging at tillering

Waterlogging is one of the limiting factors influencing durum wheat (Triticum durum L.) production. In this paper we investigated the impact of seven waterlogging durations of 4, 8, 12, 16, 20, 40, and 60 days, imposed at 3-leaf and 4-leaf growth stages, on grain yield, grain yield components, straw and root dry weight and nitrogen concentration of grain, straw, and roots of two varieties of durum wheat. Grain yield of both varieties showed a significant reduction only when waterlogging was prolonged to more than 20 days, and 40-d and 60-d waterlogging reduced grain yield by 19% and 30%. Waterlogging depressed grain yield preventing many culms from producing spikes. It slowed down spikelet formation, consequently reducing the number of spikelets per spike, and reduced floret formation per spikelet, thus reducing the number of kernels per spike