Waterlogging in wheat and barley and its effect on grain yield generation

DE SAN CELEDONIO RP; ABELEDO LG; MIRALLES DJ

Bento Goncalves

Congreso; 6th International Crop Science Congress; 2012

International Crop Science Society

Waterlogging induces reductions in yield of grain crops, and the magnitude of that loss depends on the crop phenological stage when waterlogging occurs. Under farm conditions, yield losses as a result of waterlogging are often lower in wheat than in barley. However, it is not well-identified the ontogenic stages where waterlogging is more detrimental to reduce yield and the ecophysiological mechanisms involved in the response of wheat and barley to that stress. The objective of the work was to study the effect of short-term waterlogging events during ontogeny of wheat and barley on yield generation in order to indentify the most susceptible period to the stress. For that purpose, two experiments were carried out under contrasting environmental conditions (sowing in July, under greenhouse, and sowing in September, under field conditions), where one wheat and one barley cultivars were exposed to five sequences of waterlogging events from emergency to physiological maturity (L1-L4, L4-L7, L7-L10, L10-At, At-PM; where L: number of leaf appeared in the main stem, At: anthesis, PM: physiological maturity) with a duration of 15-20 days each event. Yield losses were between 0-74% for barley and 4-92% for wheat, depending on sowing date and the moment when waterlogging was imposed. Main losses in yield were, in both species, with treatments immediately previous to anthesis (mean losses respect to the control of 66% in barley and 85% in wheat), and reductions where greater with the latest sowing date. In barley, yield losses were explained by reductions in total biomass at maturity while in wheat yield reductions were associated with decreases in both biomass at maturity and harvest index. Number of spikes per plant was the main numerical component affected in barley, while yield losses in wheat were associated with reductions in number of grains per spike. Grain weight (in main stem and tillers) was also strongly affected in both species with waterlogging events previous to anthesis and during grain filling period. To conclude, waterlogging negatively affected grain yield of wheat and barley with similar magnitude, but the yield sub-components were differently affected between species. Timing around anthesis was identified as the most susceptible period to waterlogging in wheat as well as in barley. Exposing the crop to a more stressful environment, by delaying the sowing date, magnified the response but it did not modify the sensitive timing to waterlogging.