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

Authors: ANTONY, RESHMA - Kansas State University; KIRKHAM, MARY BETH - Kansas State University; TODD, TIMOTHY - Kansas State University; Bean, Scott; Wilson, Jeff; Armstrong, Paul; Maghirang, Elizabeth; Brabec, Daniel - Dan

Submitted to: Journal of Crop Improvement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2019
Publication Date: 3/28/2019
Citation: Antony, R., Kirkham, M., Todd, T., Bean, S.R., Wilson, J.D., Armstrong, P.R., Maghirang, E.B., Brabec, D.L. 2019. Low-temperature tolerance of maize and sorghum seedlings grown under the same environmental conditions. Journal of Crop Improvement. 33(3):287-305. https://doi.org/10.1080/15427528.2019.1579139.
DOI: https://doi.org/10.1080/15427528.2019.1579139

Interpretive Summary: Though maize (Zea mays L.) is generally considered to be a more cold tolerant crop than sorghum [Sorghum bicolor (L.) Moench], however no studies have directly compared the ability of the two crops to tolerate cold conditions when grown together under the same environmental conditions. Therefore, the objective of this experiment was to directly compare the cold tolerance of maize and sorghum at the seedling stage. Seeds from both crops were analyzed for size and biochemical characteristics to determine if seed characteristics were related to cold tolerance. Seeds of both crops were germinated and grown under cold stress and the size and weight of resulting seedlings measured. For maize under the control and cold temperatures at the end of the experiment, average seedling heights were 96.1 cm and 4.6 cm, respectively; shoot dry weights were 4.16 g and 0.03 g, root dry weights were 1.81 g and 0.03 g, and leaf areas were 805.3 cm2 and 7.5 cm2, respectively. For the sorghum under the control and cold temperatures at the end of the experiment, average seedling heights were 55.5 cm and 1.4 cm, respectively; dry weights and leaf areas of the sorghum under the cold temperatures were too small to measure. The results confirmed that maize is more cold tolerant than sorghum.

Technical Abstract: Even though maize (Zea mays L.) is considered to be more cold tolerant than sorghum [Sorghum bicolor (L.) Moench], apparently no studies have directly compared the ability of the two crops to tolerate cold conditions when grown together under the same environmental conditions. Therefore, the objective of this experiment was to compare their cold tolerance at the seedling stage. Seeds also were analyzed for size and biochemical characteristics. 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 oC, day/night) and cold air temperatures (11/8 oC for 14 days; 12.5/9.5 oC for 14 days; and 14/11 oC for 3 days). Both maize and sorghum emerged when the cold temperatures reached 12.5/9.5 oC; 100% and 18% of the emerged maize and sorghum seedlings survived, respectively. For maize under the control and cold temperatures at the end of the experiment, average seedling heights were 96.1 cm and 4.6 cm, respectively; shoot dry weights were 4.16 g and 0.03 g, root dry weights were 1.81 g and 0.03 g, and leaf areas were 805.3 cm2 and 7.5 cm2, respectively. For the sorghum under the control and cold temperatures at the end of the experiment, average seedling heights were 55.5 cm and 1.4 cm, respectively; dry weights and leaf areas of the sorghum under the cold temperatures were too small to measure. For the 18 sorghum genotypes, an inverse relation was observed between seed protein concentration and seed starch concentration (R2 = 0.69). Average widths of the maize and sorghum seeds were 7.9 mm and 2.6 mm, respectively. The results confirmed that maize is more cold tolerant than sorghum.