Harvest / Post harvest

DA meter IAD maturity classes: Database

Preliminary results on IAD Maturity classes for selected Stonefruit

Fruit maturity »ImmatureHarvest readyMature
Maturity class  »Pre-climactericOnset climactericClimacteric
Ethylene production »NoneLowMed. to high
Storage potential* »Not recommendedLongShort
CultivarFruit typeSeasonalityIADIADIAD
Golden MayApricotMid> 1.201.19 - 0.60< 0.59
Rose BrightNectarineEarly> 1.001.00 - 0.40< 0.40
Majestic Pearl> 1.201.20 - 0.80< 0.80
Summer BrightMid> 0.700.69 - 0.30< 0.29
Fire Sweet> 1.000.99 - 0.50< 0.49
Summer Flare 26> 1.000.99 - 0.60< 0.59
Summer Flare 34> 1.201.19 - 0.60< 0.59
August BrightLate> 0.900.90 - 0.40< 0.40
August Fire> 1.000.99 - 0.50< 0.49
Autumn Bright> 1.001.00 - 0.60< 0.60
September Bright> 1.201.20 - 0.50< 0.50
September Red> 1.101.09 - 0.60< 0.59
O'HenryPeachEarly> 0.900.90 - 0.60< 0.60
Snow Flame 23> 0.900.90 - 0.30< 0.30
Ice PrincessMid> 1.301.30 - 0.50< 0.50
Red Haven> 1.601.60 - 0.60< 0.60
Snow Flame 25> 1.001.00 - 0.60< 0.60
August FlameLate> 1.301.30 - 0.70< 0.70
O'Henry> 1.201.20 - 0.70< 0.70
September Sun> 1.201.20 - 0.80< 0.80
AngelenoPlumLate> 1.301.29 - 1.00< 0.99

*Guide only

IAD and the DA meter

The DA meter measures the flesh greenness by reflectance at two wavelengths (670 and 720 nm) of light, near the chlorophyll-a absorbance peak. The reflectance is expressed as an index of absorption difference (IAD) scaled from 0 (fully ripe) to 3 (immature). Comparison of IAD with fruit ethylene production has shown a strong inverse relationship supporting the DA meter as a useful tool to measure fruit maturity.