Yield sensitivity to pre-anthesis heat waves in wheat and barley

CARRERA, CONSTANZA S; SLAFER, GUSTAVO A.; SAVIN, ROXANA

Rennes

Congreso; XVIII Congress of the European Society for Agronomy (ESA); 2024

European Society for Agronomy (ESA)

1. IntroductionClimate change is increasing the frequency and duration of heat waves worldwide, decreasing growth and yield of most field crops1. In this scenario, it is crucial to recognise any differences in sensitivity between wheat and barley, crops that are grown alternatively in the same fields. As far as we are aware, there are no field studies comparing wheat and barley responses to heat waves. Therefore, we compared yield sensitivity of these two cereals to pre-flowering heat waves, analysing the responses of grain number per unit area (GN/m2) and its components under field conditions. 2. Materials & methodsIrrigated and fertilised field experiments were conducted for two years (Exp 1 and Exp 2) at Bell-lloc (NE Spain). Treatments consisted of three well-adapted and high-yielding cultivars of bread wheat (Camargo, Fortunato, Klima) and two-rowed barley (Centella, Meseta, Pewter), exposed to two temperature treatments: unheated (control) and heated plots during 10 effective days in pre-flowering, using portable tents with transparent polyethylene films2. At anthesis, we determined the fertile florets number /spikelet. At maturity, we determined yield, biomass, spikes/m2, GN/m2, GN/spike and GN/spikelet. 3. ResultsHeat waves resulted in reductions in yield that were different between cultivars and years (Fig.1). The effect was much stronger in the first than in the second year (Fig.1). Averaging across the cultivars of each species, the reductions in yield were higher in wheat than barley in Exp 1, but mainly because the extreme sensitivity of Klima and the very small sensitivity of Pewter, the other two cultivars of each crop had similar reductions (Fig.1a). Yield reductions were similar between species in Exp 2 (Fig.1b). It must be noted that the actual heat load reached with the portable tents was noticeably higher in Exp. 1 than in Exp 2, and also slightly higher in barley than in wheat. Biomass reductions were in general smaller than yield reductions (i.e.,19% on average across experiments) and similar in both crops and experiments (Fig.1c,d). As expected, yield reductions were mainly associated with GN/m2 decreases (Exp 1: R2=0.93, P