Low-temperature tolerance of maize and sorghum seedlings grown under the same environmental conditions

ABSTRACT

Even though maize (Zea mays L.) is considered to be more cold tolerant than sorghum [Sorghum bicolor (L.) Moench], no studies have directly compared the ability of the two crops to tolerate low temperature when grown together under the same environmental conditions. Therefore, the objective of this experiment was to compare the low-temperature tolerance of the two crops at the seedling stage. A second objective was to analyze seeds for size (width and weight) and biochemical characteristics (content of protein, starch, and amylose). Five commercial hybrids of maize and 18 genotypes of sorghum were maintained in growth chambers for 31 days at two temperatures: a control air temperature (25/20°C, day/night) and low temperatures of the air (11/8°C for 14 days; 12.5/9.5°C for 14 days; and 14/11°C for 3 days). Both maize and sorghum seedlings emerged when the low temperatures reached 12.5/9.5°C; 100 and 18% of the emerged maize and sorghum seedlings survived, respectively. At harvest of maize under the control and low temperatures, mean shoot dry weights per plant were 4.16 g and 0.03 g, respectively. At harvest of sorghum under the control temperature, mean shoot dry weight per plant was 1.33 g. The sorghum plants grown under the low temperatures were too small for measurement of shoot dry weight. Mean widths of the maize and sorghum seeds were 7.9 mm and 2.6 mm, respectively. Maize was found to be more low-temperature tolerant than sorghum, perhaps attributable, in part, to its larger seed size.

KEYWORDS:

• Amylose
• cold stress
• protein
• Sorghum bicolor (L.) Moench
• starch
• Zea mays L

Acknowledgments

The research was funded by the Department of Agronomy, Kansas State University. This is Contribution Number 19-014-J from the Kansas Agricultural Experiment Station. Names are necessary to report factually on available data; however, the U.S. Department of Agriculture neither guarantees nor warrants the standard of the product, and use of the name by the U.S. Department of Agriculture implies no approval of the product to the exclusion of others that may also be suitable. We thank the following people: Dr. Ramasamy Perumal, sorghum breeder, Kansas State University, Hays, KS, for providing the ARCH sorghum seeds, the NAM sorghum seeds, and the Pioneer 8500 hybrid sorghum seeds; Michael Lenz, Innovative Seed Solutions LLC, Mt. Hope, KS, for providing the Dekalb 41-50 hybrid sorghum seeds; Dr. Ignacio Ciampitti, Associate Professor of Crop Production, Kansas State University, for providing the hybrid maize seeds; Kevin Fay, Physical Science Technician, USDA, ARS, Plains Area, Center for Grain and Animal Health Research, Manhattan, KS, for protein analysis; and Ms. Vu Hein, Biological Science Technician, USDA, ARS, Plains Area, Center for Grain and Animal Health Research, Manhattan, KS, for help with the starch and amylose analyses.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research was funded by the Department of Agronomy, Kansas State University. This is Contribution Number 19-014-J from the Kansas Agricultural Experiment Station.