How to make apples larger, redder

Covering orchard floors with reflective films can significantly improve fruit size, colour in warmer environments and boost apple growers' profits, say researchers.

Gala apples have become very popular in Europe, where the high quality of this fruit is increasingly appreciated by consumers.

However, to meet consumer demand, apple growers in southern Europe (mainly Spain and Italy) are looking for ways to turn out high-quality, cost-effective apple crops despite a climate that is not particularly conducive to apple production.

During the study, Spanish researchers Ignasi Iglesias and Simo Alegre used Extenday and Solarmate films and installed them 5 weeks before commercial harvest in orchards of 'Mondial Gala' apples.

They sought to determine how different types of reflective film affect orchard temperature, skin-colour development, fruit quality, light canopy distribution, and, ultimately, apple crop profitability.

The findings revealed that use of Extenday or Solarmate films resulted in an increase of 26pct in fruit size and 17pct increase in colour.

The researchers concluded that "season clearly affected fruit colour development, whereas harvest date, fruit firmness, fruit size, soluble solid concentration, titratable acidity, and maturity were not consistently affected by the use of reflective film."

According to Iglesias, the study results are promising, but long-term benefits of the technique will largely depend on fruit prices.

The study appears in recent issue of HortTechnology.