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Summary of temperature requirements for each growth stage of corn
Overview
Corn is a crop that has different temperature requirements for each stage of growth, and appropriate temperature control greatly influences growth, yield, and quality from germination to harvest. In this article, we will organize the temperature requirements for each major growth stage (optimal_min, optimal_max, base_temperature, low_stress_threshold, high_stress_threshold, max_temperature, frost_threshold, sterility_risk_threshold (flowering period only)), focusing on public agricultural institutions and peer-reviewed papers in Japan and abroad. A comprehensive explanation is provided, including the definition of each parameter, the corresponding value, and notes on regional differences and variations.
Definition of each parameter
- base_temperature (base temperature) : The minimum temperature at which each growth stage starts. Growth reactions do not occur below this temperature.
- optimal_min, optimal_max (optimal minimum/optimal maximum temperature): The lower and upper limits of the ideal temperature range for the best growth at each stage.
- low_stress_threshold (low-temperature stress threshold): The temperature below which stress, delay, and failure are likely to occur in growth, germination, etc.
- high_stress_threshold (high-temperature stress threshold): The temperature above which poor growth and damage due to high temperatures are likely to occur.
- max_temperature : Maximum temperature that can be tolerated before sudden failure or fatal effects occur.
- frost_threshold : The lowest temperature at which lethal damage or significant quality loss due to freezing occurs.
- sterility_risk_threshold (Sterility risk threshold, flowering period only): Temperature above which the risk of sterility and fertilization problems such as pollen/ovules increases significantly.
Temperature requirements for each growth stage
1. Germination period (sowing - budding)
Definition: From seed sowing to above-ground germination
Main varieties/Japanese conditions: Sweet corn, general corn
Parameters:
Parameter Value Unit Remarks base_temperature 10 to 11 °C Lower limit. 11°C has some domestic data values [12] optimal_min 20 °C Sweet corn recommended [15] optimal_max 28 to 29.3< /td> °C Overseas general value is 29.3°C[1][15] low_stress_threshold 13～14 °C Lowest soil temperature for sowing [13][15] high_stress_threshold Not specified - max_temperature 40 (germination threshold) °C Global upper limit of sudden high temperature during germination [1] frost_threshold 0 °C Damage below 0°C [2][17] sterility_risk_threshold Not applicable - Regional differences and variations:
- In Japan: Cool regions (Hokkaido, etc.) place emphasis on securing soil temperature. Super sweet varieties are particularly susceptible to low temperature germination [15].
Definition: After germination, tillering/leaving to the start of tassel differentiation
Parameter:
Parameter Value Unit Remarks base_tem perature 10 °C Common to each document [2][6] optimal_min 22 °C Domestic standard [15] optimal_max 30 °C Domestic recommended upper limit [15] low_st ress_threshold 10 °C Growth stops below 10°C [2][5] high_stress_threshold 30 °C Growth delay/abnormality if exceeded [2][15] max_temperature 40 °C Global budding resistance [1] frost_threshold 0～-2 °C Light resistance at underground growth point up to V5-V6. [17] sterility_risk_threshold Not applicable - Regional differences and variations:
- Japanese standard: Recommended soil temperature of 13 to 14°C or higher (appropriate sowing period), avoidance of late frost risk [13][15].
Definition: From earing to pollen release, from appearance of silk to completion of pollination
Parameter:
Parameter Value Unit Remarks base_temperature 10 °C [2][6] optimal_min 22 °C [15] opt imal_max 30 °C [15] low_stress_threshold 20 °C Less than 20°C [2] high_stress_threshold 35 °C Sterility increases at temperatures above 35°C [1][3][20][22] max_temperature 35～36 °C Sudden decline in pollen survival [1][3] frost_thre shold 0 (Lethal -1) °C Tissue freezing damage below 0°C [2][17][19] sterility_risk_thr eshold 35 (28-30 at night also affects) °C Sterility risk is maximized at over 35°C in daylight + over 28°C at night [1][2] Regional differences and variations:
- In Japan, cool regions such as northern Japan are the main areas, and the risk of high temperature during flowering has been increasing in recent years.
- The sterility risk threshold is widely recognized worldwide at around 35°C [1][3][20].
4. Ripening/maturation stage (Grain filling-Physiological maturity: End of pollination-Black layer formation)
Definition: From completion of fertilization to ripening of ears and formation of black layer (appropriate harvesting period)
Parameters:
Parameter Value Unit Remarks base_temperature 10 °C [6] optimal_min 22 °C [15][16] optimal_max 30 °C [15][16] low_stress_threshold 15～16 °C Grain weight and ripening delay below 16°C [15] high_stress_threshold 35 °C Fulfilling failure above 35°C [20][22] max_temperature 35 °C Inhibition of grain development during ripening [20] frost_threshold -1 to -2 °C Before physiological maturity Ear and stock necrosis due to freezing [2][17][19] sterility_risk_threshold Not applicable - Regional differences and variations:
- In northern Japan to Hokkaido, there is a high risk of early frost in autumn, and if the temperature drops below -1°C before maturity, significant yield loss and quality deterioration will occur [17][19].
Parameter not reported/Variations/Notes
- Some parameters (especially "maximum temperature" and "stress threshold") often do not have individual values for each growth stage.
- ``Low temperature stress threshold,'' ``maximum temperature,'' and ``sterility risk threshold'' are mainly discussed at the flowering and ripening stages.
- Although there are differences between varieties and regions, the temperature range is generally the same in both Japanese official guidelines and foreign papers.
- It is also important that the flowering period is impaired by high temperatures at night (the risk of sterility increases, especially at night temperatures of 28-30°C or higher) [2].
Summary table
Growth stage base_temp optimal_min optimal_max low_stress high_stress max_temp frost_threshold sterility_risk (Flowering period) Germination 10-11°C 20°C 28-29.3°C 13-14°C - 40°C 0°C - Vegetative growth 10°C 22°C 30°C 10°C 30°C 40°C 0～-2°C - Flowering 10°C 22°C 30°C 20°C 35°C 35-36°C 0 (Lethal -1°C) 35°C (28-30°C at night) Ripening/ripening 10°C 22°C 30°C 15～16°C 35°C 35°C -1～-2°C - (all in °C)
Key points for cultivation management in Japan
- Suitable time for sowing: If the soil temperature is below 13-14°C, there is a big risk to germination and early growth. Early sowing carries the risk of late frost and low soil temperature [13][15].
- High temperature during flowering period (especially over 35°C during the day and over 28°C at night): Environmental management during the flowering period is important as sterility and fertilization problems increase [1][2].
- Autumn frost risk: If the temperature drops below -1°C with immature grains and green stems and leaves, yields will decrease significantly and ripening will be poor. Management during maturity is especially important in cool regions [17][19].
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References
Sources
[1] Annual Report 2014 (JIRCAS): https://www.jircas.go.jp/sites/default/files/publication/annual_report/annual_report_2014_0.pdf
[2] Agrometeorological Requirements of Maize Crop Phenology (MDPI): https://www.mdpi.com/2071-1050/13/14/7719
[3] Implications of climate change for agricultural productivity in ... (NRID): https://acsess.onlinelibrary.wiley.com/doi/abs/10.1002/agj2.20721
[6] AGR-202: Corn Growth Stages and Growing Degree Days (UKY): https://publications.mgcafe.uky.edu/sites/publications.ca.uky.edu/files/agr202.pdf
[12] Maize host information - Ministry of Agriculture, Forestry and Fisheries: https://www.maff.go.jp/j/syouan/nouan/carta/c_data/pdf/syukusyu_maize.pdf
[13] Section 8 Sweet Corn (PDF: 452KB): https://www.maff.go.jp/j/seisan/kankyo/hozen_type/h_sehi_kizyun/pdf/miyagi_yasai18_11.pdf
[14] Maize - BSI Institute of Biological Sciences: https://bsikagaku.jp/cultivation/maize.pdf
[15] Sweet corn - Takii seedlings: https://www.takii.co.jp/tsk/manual/corn.html
[16] Threshold temperatures for different growth stages in maize: https://corn.agronomy.wisc.edu/Management/L041.aspx
[19] Fall Frost and Corn Maturity - Bayer Crop Science: https://www.cropscience.bayer.us/articles/bayer/fall-frost-and-corn-maturity
[20] Thresholds and extent of temperature effects on maize yield differ in ... (PubMed): https://pubmed.ncbi.nlm.nih.gov/38325451/
[22] Maize Adaptability to Heat Stress under Changing Climate (InTechOpen): https://www.intechopen.com/chapters/72199
- In Japan: Cool regions (Hokkaido, etc.) place emphasis on securing soil temperature. Super sweet varieties are particularly susceptible to low temperature germination [15].