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

Romina de San Celedonio1,2, L. Gabriela Abeledo1,2 and Daniel J. Miralles1,2,3 1Cátedra de Cerealicultura, Departamento de Producción Vegetal, Facultad de Agronomía, Universidad de Buenos Aires; 2CONICET; 3IFEVA. Av. San Martín 4453 (C1417 DSE), Buenos Aires, Argentina. E-mail: romina@agro.uba.ar Waterlogging induces reductions in yield of grain crops and the magnitude of the yield loss depends on the crop phenological stages 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 otogenic stages where waterlogging is more effective to reduce yield and the ecophysiological mechanisms involved in the response of wheat and barley to waterlogging. The objective of the present 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 excessive water. 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 (5) sequences of waterlogging events from emergency to physiological maturity (L1-L4, L4-L7, L7-L10, L10-At, At-PM; being L: number of leaf appeared in main stem, At: anthesis, PM: Physiological Maturity) with a waterlogging duration of 15-20 days each period. 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, for both species, in treatments immediately previous to anthesis (losses of 66% in barley and 85% in wheat, respect to the control), and reductions where greater with the latest sowing date. In barley, yield losses were mainly explained by reductions in total biomass at maturity while in wheat yield reductions were associated with penalties in both biomass at maturity and harvest index. Number of spikes per plant was the main numerical component affected in barley, while in wheat yield losses were associated with reductions in number of grains per spike. Grain weight was also strongly affected by waterlogging in both species (in main stem and tillers) especially when treatments were applied 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 depending on the specie. The timing around anthesis was identified as the most susceptible 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