Critical period for yield determination across grain crops

Studies across different crops demonstrated that grain or seed number per unit area (GN m –2 ) is the dominant yield component. Although grains or seeds derive from floret or flower production and survival, the timing of the critical period for GN m –2 determination is known to vary noticeably, from mainly pre-flowering to strongly post-flowering, across major grain crops. Here, we demonstrate that discrepancy between crops in the timing of their critical period is related to the flowering phase duration and the proportion of the whole cycle allocated to pre-flowering development. Changing the perspective, positioning the critical period at the end of the phase when grain abortion occurs instead of flowering, results in the critical period virtually coinciding among contrasting grain crops.