Grain yield responses to pre-flowering heat waves in wheat and barley: inter and intraspecific genotypic variations.

CARRERA CONSTANZA S; SLAFER GUSTAVO; SAVIN ROXANA

Potsdam

Congreso; XVII congress of the European Society for Agronomy (ESA); 2022

European Society for Agronomy

Given the current trend of rising temperatures, the probability of heat stress will increase, thus compromising food security due to the negative effects on the performance of most crops. In this context recognizing differences in sensitivity between crops that are grown alternatively on the same fields, like wheat and barley, may be relevant. Barley is frequently considered to be better adapted to stressful environments than wheat. This difference is mostly assumed regarding water stress (although hard evidences not always agree with this assumption). However, to the best of our knowledge, there have been no studies comparing sensitivity of wheat and barley to heat waves. Besides, the fact that there must be intraspecific genotypic variation in that sensitivity is certain for both cereals. In this presentation, we will report the results of a field experiment aimed to (i) determine for the first-time interspecific differences between wheat and barley in responses to heat waves at pre-flowering stage, (ii) quantify the intraspecific variation among current cultivars, and (iii) ascertain physiological traits, avoiding the confounding effects of changes in phenology, that are often responsible for the plasticity in response to heat. Uncovering true differences in tolerance to heat across well-adapted and high-yielding cultivars, within the same phenological pattern, is relevant for having sound decisions on the preference of growing one crop or the other. The experiment comprised three current cultivars of each wheat and barley in factorial combination with two levels of heat: an unheated control and plots heated for a brief period using portable chambers with transparent polyethylene films placed over the plots, immediately before flowering. We analysed the dynamics of floret initiation and survival, the resulting changes in spike fertility and possible trade-offs with the average grain weight.