Compared to other crops, maize production demands relatively high temperatures. However, temperatures exceeding 35°C lead to adverse effects on maize yield. High temperatures (≥35°C) are consistently experienced by summer maize during its reproductive growth stage in the North China Plain, which is likely to cause irreversible crop damage. This study investigated the effects of elevating temperature (ET) treatment on the yield component of summer maize, beginning at the 9th unfolding leaf stage and ending at the tasseling stage. Results demonstrated that continuous ET led to a decrease in the elongation rate and activity of silks and an elongated interval between anthesis and silking stages, and eventually decreased grain number at ear tip and reduced yield. Although continuous ET before tasseling damaged the anther structure, reduced pollen activity, delayed the start of the pollen shedding stage, and shortened the pollen shedding time, it was inferred, based on phenotypical and physiological traits, that continuous ET after the 9th unfolding leaf stage influenced ears and therefore may have more significant impacts. Overall, when maize plants were exposed to ET treatment in the ear reproductive development stage, the growth of ears and tassels was blocked, which increased the occurrence of barren ear tips and led to large yield losses.
