Reconciling apparent differences among field crops on their critical periods for yield determination

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

Braga

Congreso; Iberian Plant Biology 2023; 2023

Portuguese and Spanish Societies of Plant Biology

Further increases in the yield of field crops continue to be a high priority to meet the projected rises in agricultural product demand. Studies repeatedly demonstrated across different crops that the number of grains/seeds per unit of land area (GN m-2) is the dominant component of yield. Although grains/seeds derive from floret/flower production and survival, the timing of the critical period for GN m-2 determination is known to vary noticeably, from mainly pre-flowering (e.g. wheat) to strongly post-flowering (e.g. soybean), across major crops. In this work, we reviewed evidences for three major and contrasting field crops: wheat, maize, and soybean aiming to demonstrate that the differences in timing of their critical period for GN m-2 determination may be more apparent than real. The main sources of the apparent discrepancy are related to the duration of the flowering phase and the proportion of the whole cycle allocated to the onset of flowering. Having these two differences in mind, we propose a change in perspective, referring the critical period to the end of the phase when grain abortion could occur instead to flowering resulting in a critical period virtually coinciding for what are considered contrasting field crops. Our findings may have important implications for strengthening the evolutionary basis of the universal plasticity of grain/seed number. On the evidence that reproductive biology relies on evolutionary principles, the behavior for all crops should be very similar, and this work reconciles the apparent conflict with that premise. This study may also provide insights that might be used directly in the development of broader physiological models for all field crops.