Quantifying Temperature Effects on Corn Growth and Development.

Temperature is a primary determinant of Corn (Zea mays L.) growth and developmental rates. Outside of the desirable range, extreme temperatures (high and low) lead to suboptimal growth and development, often resulting in unrealized yield loss at the end of the season. The objectives this study were to quantify temperature’s relationship with corn growth and developmental rates, focusing on shoot and root phenotypic traits. Plants were grown in Soil-Plant-Atmospheric-Research (SPAR) units: controlled, sunlit growth chambers allowing precise control of environmental factors such as temperature, CO₂, soil moisture, among others. These units allow plants to grow under nearly ambient solar radiation similar to field conditions. Two experiments were conducted to determine the effect of temperature on corn growth and development over the first four weeks of vegetative growth. Temperature treatments were imposed upon emergence. Shoot and root measurements were taken weekly by harvesting a small number of plants. Plant height, leaf number, and leaf area were measured. Root systems were washed and scanned for computer analysis. Plant parts were separated for dry weight measurements. Physiological measurements, including photosynthesis and plant pigment traits, were taken four weeks post-emergence. Temperature had a significant impact on growth and developmental rates of the shoot and root traits throughout the first four weeks post-emergence. Environmental productivity indices (EPIs) were created to allow comparison of the effect of temperature on all measured phenotypic traits. Root and shoot traits; growth and development traits; and physiological traits all differed in response to temperature and held different optimal temperatures.