Early Drought Can Reduce Maizeggrain Yield By Shifting Both the Time of Pollen Shedding and Silking without Extending the Anthesis Silking Interval.

The anthesis-silking interval (ASI) has been regarded as a critical factor for maize (Zea mays L.) grain yield when water deficit stress occurs around flowering. However, water deficit can occur at any time during the growing season. To explore the relationship between maize grain yield and ASI in response to water deficit at different growth stages, experiments were conducted in the rain shelter during three successive years and included four water deficit periods: 6 to 8-leaf (V_6-8), 9 to 12-leaf (V_9-12), 13 leaf to tasseling (V_13-T), and silking to blister stages (R_1-2). Results showed greater reduction in maize grain yield associated with water deficit stress later in development. Interestingly, grain yield was related more closely to the timing of silking than the ASI when water deficit stress was imposed prior to silking. Among all treatments, silking occurred last for V_13-T, which resulted in the longest ASI and the lowest grain yield. Nonetheless, maize grain yield also decreased in response to earlier water deficit stress (V_6-8 and V_9-12) which caused delayed silking but no or decreased ASI. Water deficit stress during V_6-8 delayed male and female reproductive organ without influencing ASI. However, for the V_9-12 treatment, the development of male reproductive organs was delayed more than that of female organs. In contrast, for the V_13-T treatment, female reproductive organ development was delayed more than development of male organs. These data suggest that the time of silking plays a more important role than ASI for maize grain yield when water shortage occurs pre-silking (V₆-V_T).