Elevated temperature and moisture deficit stress impact on phenology, physiology and yield responses of hybrid maize

A field experiment was conducted with maize (Zea mays L.) hybrid DHM-117 under elevated temperature and moisture deficit stress to assess the phenology, physiology, biomass and yield responses. The elevated canopy temperature (ET) was maintained as 3°C above ambient canopy temperature (AT) in Free Air Temperature Elevation (FATE) facility and water deficit stress (WD) was imposed at initiation of tasseling stage in an open plot experiment to assess the impact of these two abiotic stresses. As compared with ambient control, the phenology of flowering with the ET was early as 3 days for anthesis, 1 day for silking and this increased 4 days for anthesis silking interval (ASI), while with WD, anthesis was delayed by 2 days, silking by 3 days and ASI increased by 3 days. It was observed that both ET and WD significantly decreased photosynthetic rate (32%, 24%), stomatal conductance (45%, 28%), transpiration rate (36%, 44%) while increased WUE (6%, 38%). It is interesting to record that there was reduction in total biomass (11%, 13%) especially reproductive biomass (44%, 31%) with both ET and WD while vegetative biomass was improved (27%, 8%) revealing that reproductive components are effected with these abiotic stresses thereby decreased HI (42%, 36%). The impact of ET was more on seed set than seed filling as the reduction in test weight (8%) was higher than at WD (4%).