Yield strategies under water deficit conditions in winter cereals

BARNADA, F.J.; MIRALLES, D.J.; DIEZ, M.M.; ALVAREZ PRADO, S.

Rosario

Congreso; XXXIV Argentinian Meeting of Plant Physiology; 2023

Bread wheat (BW) and barley (BL) are the most important winter cereals in crop rotations, while triticale (TC) and durum wheat (DW), although represent a minor area, they stand out for their tolerance to water deficit. The aim of this study was to identify the yield strategies of BW, BL, TC and DW when exposed to contrasting water conditions i.e irrigated (IR) and deficit (WD) during crop cycle. Grain yield ranged from 316 to 1031 g.m-2 under irrigation and from 136 to 859 g.m-2 under water deficit conditions. The ranking of tolerance to water deficit, measured as yield reduction under WD respect to IR, was BW (18%)> BL (33%)> DW (48%)> TC (54%). Yield variability was more associated with variations in grain number (GN) rather than in grain weight (GW), except for BW and DW. GN reductions due to WD were mainly explained by reductions in grains from the main stems in TC (39%) and DW (38%) and from tillers in BL (36%), TC (66%) and DW (56%). GN reductions in BW were lower respect to the other species with 7% and 14% for main stem and tillers, respectively. Changes in GN were mostly explained by changes in number of spike per m2 (NºSP.m-2) than by changes in the number of grains per spike (NG.SP-1). Under both water conditions, BL showed the highest NºSP.m-2 (IR: 790, WD: 691 NºSP.m-2). Water availability impacted in the same way on all species. DW and TC showed significant reductions in NG.SP-1 (28% and 22%, respectively) and in spikelets per spike (SP.SP-1) (11% and 14%, respectively) under water deficit conditions. BW was the most tolerant species to water deficit, as NG, NG.SP-1 and SP.SP-1 did not show significant changes as was observed in DW and TC. Finally, BL only reduced the NºSP.m-2.