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Detailed Survey of Growing Degree Days (GDD) by Growth Stage for Potato
Overview
Growing Degree Days (GDD) are an important indicator for potato growth management and harvest timing prediction. This report identifies the GDD required at each growth stage—Sprouting, Emergence, Vegetative growth, Tuber Initiation, Tuber Bulking, and Flowering—based on domestic and international primary literature and official research institution materials. Japanese public research is prioritized; where direct GDD values are unavailable, estimates are made from literature data with the basis and calculation method stated explicitly.
GDD Calculation Method and Reference Values
- GDD is calculated by summing daily temperatures above a base threshold (daily mean temperature − base temperature) that contribute to crop growth over the growing period.
- The base temperature (Tbase) for potato is generally 4°C in Japan and internationally (some literature cites 2°C, but the international standard is 4°C) [1][2][3].
- GDD = Σ (daily mean temperature − base temperature); if daily mean is below base temperature, 0 is added for that day.
GDD Values by Growth Stage from Domestic Research
Classification by Hokkaido Agricultural Research Center
Official research materials from the Hokkaido Agricultural Research Center divide potato growth into three intervals and present effective accumulated temperature (effective GDD) for each [1].
Intervals and GDD Values
| Growth Stage | GDD (°C·days) |
|---|---|
| Planting to sprouting (Sprouting–Emergence) | 170 |
| Sprouting to tuber initiation (Emergence–Tuber Initiation) | 150 |
| Tuber initiation to growth cessation (Tuber Initiation to end of growth) | 1675 |
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- This classification aligns with European models (e.g., WOFOST) and has become the standard GDD management approach in Japan.
- Transfer of assimilates to tubers (full onset of tuber bulking) begins after 150°C·days after sprouting (Emergence → Tuber Initiation) [1].
Mapping Growth Stages to GDD Values
1. Sprouting
- Interval: Planting to sprouting
- GDD: 170°C·days
- Description: Period after planting until seed tuber sprouts emerge above the soil surface.
2. Emergence
- Interval: Sprouting
- GDD: Emergence completes at 170°C·days
- Description: When sprouts appear above the soil (Sprouting and Emergence are practically the same interval in field management).
3. Vegetative Growth
- Interval: Sprouting to tuber initiation
- GDD: 150°C·days (Emergence to Tuber Initiation)
- Description: Above-ground stem and leaf expansion before transition to reproductive growth.
4. Tuber Initiation
- GDD milestone: 320°C·days after planting (170 + 150 = 320°C·days)
- Description: Point at which tuber bulking begins underground in addition to above-ground growth.
5. Tuber Bulking and Maturity
- Interval: Tuber initiation to growth cessation (physiological maturity)
- GDD: 1675°C·days
- Notes: This interval includes Flowering, Tuber Bulking, and Maturity; domestic and international GDD literature and administrative materials do not further subdivide it [1][4][5].
6. Flowering
- GDD value: No subdivided value provided
- Estimate: Domestic and international research does not manage flowering as an independent GDD interval. Flowering typically occurs 2–4 weeks after sprouting, overlapping with Emergence–Tuber Initiation or early Bulking in cumulative GDD terms [3][6].
International GDD Values and Comparison with Domestic Data
- Recent international reviews and cultivation guides also center GDD on three intervals: Emergence, Tuber Initiation, and Physiological Maturity [3][4][5].
- Cumulative GDD to maturity is approximately 1250–1700°C·days (Tbase = 4°C). The Hokkaido value (total: 1995°C·days) falls within this range [1][3][4].
- Primary sources rarely assign separate GDD values to Flowering or Bulking alone.
Limitations of GDD Stage Division and Estimation Methods
- Japanese and international literature commonly manage GDD between sprouting, tuber initiation, and growth cessation (maturity); intermediate stages such as Flowering and Bulking are described physiologically but are not used as official GDD intervals [1][3][6][7].
- For finer subdivision, one would estimate when flowering occurs within the 1675°C·day interval from tuber initiation to growth cessation—using average days and temperature data—but no publicly documented numerical basis exists for such splits.
Recommended Practical GDD Management Intervals
Recommended GDD intervals (from domestic public research)
- Planting to sprouting (Sprouting, Emergence): 170°C·days
- Sprouting to tuber initiation (Vegetative → Tuber Initiation): 150°C·days
- Tuber initiation to growth cessation (including Bulking, Flowering, Maturity): 1675°C·days
These three intervals are the most important and practical. Separate GDD management for Flowering or Bulking alone is not generalized domestically or internationally at present.
Base temperature is 4°C; the Hokkaido Obihiro practice example is standard, and equivalent approaches apply nationwide and internationally.
Subdivision beyond official materials requires estimation based on field observation records and research data for each cultivation site and cultivar.
Sources
[1] Hokkaido Agricultural Research Center: Setting effective accumulated temperature by potato growth stage, PDF
https://www.hro.or.jp/upload/15450/4-3.pdf
[2] MAFF crop condition survey: https://www.maff.go.jp/j/tokei/kouhyou/sakumotu/sakkyou_yasai/
[3] "Base and upper temperature thresholds to support the calculation of crop coefficient curves for irrigation performance assessment; A review", Agricultural Water Management, 2025
https://www.sciencedirect.com/science/article/pii/S037837742500469X
[4] "Influence of GDD in different growth parameters of potato at agroclimatic condition of Jorhat", ResearchGate
https://www.researchgate.net/publication/355209193_Influence_of_GDD_in_different_growth_parameters_of_potato_at_agroclimatic_condition_of_Jorhat
[5] "Actual and Potential Yield Levels of Potato in Different Production Systems of Japan", Springer
https://link.springer.com/article/10.1007/s11540-016-9322-z
[6] "Accumulated growing degree days as a model to determine...", CABI Digital Library
https://www.cabidigitallibrary.org/doi/pdf/10.5555/20193084282
[7] Growth Stages Classification of Potato Crop Based on Analysis of Spectral and Chlorophyll Characteristics, PMC
https://pmc.ncbi.nlm.nih.gov/articles/PMC7411602/
[8] Future outlook for adaptation to climate change impacts, MAFF
https://www.maff.go.jp/j/kanbo/kankyo/seisaku/climate/report2018/attach/pdf/report-75.pdf