| dc.description.abstract | Water is a limiting factor when growing maize especially in arid and semi-arid environments such as the Texas High Plains. Maize (Zea mays, L.) kernel set remains vulnerable to drought stress occurring at flowering, and silk emergence is one of the key processes which limits kernel set under stress. Our objective of this research was to determine how much silk emergence differed in drought tolerant (TOL) and drought susceptible (SUS) maize hybrids and whether this was a significant genetic advantage driving yield under drought stress This study, conducted in the Texas Panhandle, compared five TOL and five SUS hybrids in a full irrigated (FI) and a drought stress (DS) environment over two years (2018, 2019) . Managed Stress Environment (MSE) techniques using sub-surface drip irrigation in this arid environment were used to impose drought stress bracketing the flowering window. Silk emergence, grain yield and yield components were evaluated for the TOL and SUS hybrids under FI and DS. The DS MSE resulted in significant reductions in silk emergence, yield, and yield components in both 2018 and 2019. Compared to the FI, the DS treatment reduced yield 33.9% over both years and all hybrids. Silk emergence was reduced 9.7% by the DS treatment. When evaluating the different genetic classes in DS, the TOL hybrid class out yielded the SUS class under DS, 9.21 Mg ha-1 vs. 8.06 Mg ha-1, respectively (p<0.0001). This represents a 30.9% and a 37.0% reduction in yield of the TOL and SUS classes, compared to yields under FI. Similarly, the TOL class exhibited higher silk ear-1 than the SUS class, 461.8 vs. 426.6, respectively (p<0.0004). This represents a 6.2% and a 13,1% reduction in silk emergence for the TOL and SUS classes, compared to their silk emergence in FI. Linear regression between silk ear-1 and yield resulted in an r2= 0.20 (p<0.0001), suggesting that the more prolific silk emergence of the TOL hybrids was responsible for a significant portion of the observed yield variation under drought. These data suggest that ongoing efforts to select hybrids for improved silk emergence and yield under drought stress at flowering will improve hybrid maize performance when water limits grain yield potential in the Texas High Plains. | en |
