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How can growers predict the mango harvest?
Quick find: this post is based on the published summary (abstract) of the study, not the full paper.
13.5% for calendar days, 1.3% for growing degree days with an upper and a lower temperature limit. Those were the coefficients of variation across site-season populations when Queensland researchers compared ways of timing the harvest of Australian mango cultivars.
Forecasting the mango harvest window from flowering helps with choosing cultivars and planning the harvest. A team from the Institute for Future Farming Systems at Central Queensland University and the Department of Agriculture and Fisheries in Mareeba, Queensland, tested whether a count of growing degree days holds up better across sites and seasons than a count of calendar days, and set degree day targets for when the fruit is mature (Amaral et al., 2026).
What this means for your grow
For mango growers, the study backs a degree day count over a plain count of days: across the sites and seasons studied, the degree day count with both limits varied far less than calendar days did. The authors recommend a lower base temperature of 12 °C and an upper limit of 32 °C for all the cultivars they assessed. The published summary does not give the degree day targets for each cultivar, so there is nothing here yet to put straight into your own harvest plan.
What did they test and find?
- Three ways to count: calendar days, and accumulated growing degree days (GDD) calculated either with a lower base temperature alone or with both a lower and an upper temperature threshold. The team checked how well each held up across sites and seasons.
- The thresholds: the authors recommend operational values of 12 °C for the lower base temperature and 32 °C for the upper threshold, for all the cultivars they assessed.
- How much each varied: the coefficient of variation across site-season populations was 13.5% for calendar days, 2.5% for GDD with the lower base temperature alone, and 1.3% for GDD with both thresholds. The authors say this confirms the robustness of the bounded GDD estimate across growing environments.
- Two ways to judge maturity: one was ripening time. Fruit taking 12 days to ripen at 20 °C marked the lower maturity boundary, and 6 days the upper boundary. The other used the fruit's internal attributes at harvest: flesh colour, dry matter, soluble solids concentration, titratable acidity and flesh firmness.
- Minimum maturity: this was based on flesh colour and dry matter targets set for each cultivar, and a ratio of soluble solids concentration to titratable acidity of 7.0. The two approaches agreed closely on minimum maturity.
- Maximum maturity: at the upper ripening-time boundary, the mean firmness of groups of fruit ranged from 2.2 to 3.6 kgf, so the team used 3 kgf for individual fruit as the benchmark for the upper limit.
- Earlier figures confirmed: for ‘B74’, ‘Honey Gold’ and ‘Keitt’, the average of the two new estimates of minimum maturity differed from previously published preliminary values by only 9 to 13 °C d, about one calendar day. Values for ‘Nam Dok Mai’, ‘1201’ and ‘4069’ had not been estimated before.
- How far they got: minimum GDD values were set for nine cultivars, and complete harvest windows were worked out within the study for four.
What could it mean?
The authors present the bounded GDD estimate as robust across growing environments, and their opening point is that forecasting the harvest window from flowering aids cultivar selection and harvest planning. Right now this is a result for people choosing mango cultivars and planning mango harvests, and the published summary does not give the cultivar targets themselves.
What were the limitations?
Complete harvest windows were resolved for four of the nine cultivars. For the other five, the upper-boundary estimates were based on a single assessment approach or on legacy observations, or remained unresolved.
Trial details
- Who: Institute for Future Farming Systems, Central Queensland University, Rockhampton, Queensland, and the Department of Agriculture and Fisheries, Mareeba, Queensland, Australia (the authors’ affiliations).
- Where: more than one site, over more than one season (the abstract describes a cross-site and cross-season evaluation across site-season populations). The abstract describes the cultivars as Australian mango cultivars but does not name the sites.
- Crop: mango, nine cultivars, including ‘B74’, ‘Honey Gold’, ‘Keitt’, ‘Nam Dok Mai’, ‘1201’ and ‘4069’.
- Compared: calendar days; GDD with a lower base temperature (Tb) alone; GDD with lower and upper thresholds (Tb and TB). Recommended Tb = 12 °C and TB = 32 °C.
- Maturity measures: time to ripen at 20 °C (12 days for the lower boundary, 6 days for the upper), and flesh colour, dry matter (DM), soluble solids concentration (SSC), titratable acidity (TA) and flesh firmness at harvest. Minimum maturity: cultivar-specific flesh colour and DM targets and SSC:TA of 7.0. Upper limit: 3 kgf individual-fruit firmness benchmark.
- Results: coefficient of variation across site-season populations 13.5% (calendar days), 2.5% (GDD, Tb alone) and 1.3% (GDD, Tb and TB); mean firmness of cohorts at the upper ripening-time boundary 2.2 to 3.6 kgf; close agreement between the two estimates of minimum maturity; minimum maturity values for ‘B74’, ‘Honey Gold’ and ‘Keitt’ within 9 to 13 °C d of previously published preliminary values; minimum GDD set for nine cultivars and complete harvest windows for four.
- Funding: Hort Innovation (award MG22000), as listed in the paper’s Crossref record.
- Publication: Horticulturae 12(10), 1240, published 5 October 2026, https://doi.org/10.3390/horticulturae12101240. Licence: CC BY 4.0.
- Not reported in the published abstract: the names and locations of the sites, how many sites and seasons there were, the dates, what kind of growing site each was, tree age and rootstock, the names of the other three cultivars, the GDD targets for each cultivar, the number of trees and fruit sampled, statistics beyond those above, and conflicts of interest.
Links
- The study: Growing Degree Day Targets for Fruit Development of Australian Mango Cultivars II Harvest Windows
- The project: Managing mangoes for future climates (MG22000), Hort Innovation, delivered by Central Queensland University
References
- Amaral, M. H. P. do, Walsh, K. B., McConchie, C., & Dickinson, G. (2026). Growing degree day targets for fruit development of Australian mango cultivars II harvest windows. Horticulturae, 12(10), 1240. https://doi.org/10.3390/horticulturae12101240