Effect of drought stress and recovery on stonefruit production varies with severity, duration and timing of water deficit. This study examined fruit and tree performance under deficit irrigation in 'September Bright' nectarine.

  • Typically, fruit size was reduced under water deficit. Water deficit also lowered yield, decreased canopy size (light interception), lowered stomatal conductance, reduced leaf chlorophyll, increased photo-inhibition, increased fruit soluble solids, increased firmness, decreased maturity and increased red skin colour coverage.
  • However, moderate water deficit (40% ETc) during the traditional RDI period (Stage II of fruit growth) showed no effect on yield or fruit quality.

Precision horticulture solutions are required to deliver consistent high marketable yields and improve production efficiency. Growers need to monitor tree and fruit performance. A range of equipment and sensors are available to measure fruit size and quality and tree growth and water stress. Application of sensor systems for the assessment of fruit and tree performance can inform growers and if necessary, adjust agronomic practices within a growing season. At harvest, commercial fruit graders benchmark crop performance by providing a record for yield, fruit quality and defects to ensure high quality fruit enters the marketplace.

Measurements and equipment used during this experiment:

  • irrigation volume, water flow meter (user friendly)
  • evaporative demand and rainfall, BoM weather station (user friendly)
  • trunk and fruit diameter, digital calliper (user friendly)
  • pruning biomass, digital scales (user friendly)
  • fruit maturity, DA meter (user friendly scientific instrument)
  • leaf photosynthetic performance (efficiency of photosystem II), LICOR (scientific instrument)
  • leaf fluorescence, Fluorometer (scientific instrument)
  • leaf chlorophyll concentration, SPAD meter (scientific instrument)
  • leaf conductance, Porometer (scientific instrument)
  • canopy light interception, Ceptometer (scientific instrument)
  • fruit yield and quality (size, colour, sweetness, maturity) of individual fruit, Fruit grader with load cell, NIR sensor and RGB cameras (user friendly)