Spraying methyl jasmonate on fruit trees boosts harvest 

Spraying persimmon trees with methyl jasmonate (MeJA) can result in healthier, longer lasting fruit, with increased antioxidants a new Edith Cowan University (ECU) study has found.

MeJA is a food safe organic compound extracted from jasmine oil. The compound can be used to regulate environmental stress in fruit production, modulate fruit growth and development, improve fruit ripening.

In the first study of its kind, PhD student Mr Mahmood Ul Hasan applied MeJA as preharvest spray application to persimmon cultivars ‘Yoho’ and ‘Jiro’ grown in Western Australia, four weeks before their anticipated harvest to evaluate its effect on developing fruit colour and enhancing bioactive compounds.

“The application of MeJA resulted in bright fruit colour and enhanced ripening even after one week of spray application in ‘Yoho’ and two weeks in ‘Jiro’ persimmons, without compromising fruit quality. By enhancing the colour of early maturing cultivars, we are extending the season for those fruit by a few weeks, allowing growers to earn more income,” Mr Mahmood said.

MeJA has previously been reported for other fruit crops, including apples, oranges, mangoes, grapes and pomegranates.

Mr Mahmood noted that in ‘Yoho’ and ‘Jiro’ persimmons, the preharvest spray application of MeJA resulted in significant changes in fruit peel colour harvested at different intervals until commercial harvest.

Australia is among the top 15 persimmon growing countries of the world. In Western Australia, the harvest season usually commences in March for early season maturing cultivars.

The production and availability of persimmon is consumer driven and depend on demand in supermarkets. Advancing the harvest maturity of early maturing cultivars is a pre-requisite to attain early fruit colour development and trigger early market arrival to ensure higher economic returns to growers and expand market window of the fresh fruit, Mr Mahmood said.

Increased health benefits

In addition to enhancing fruit colour, the pre-harvest application of MeJA also resulted in increased health promoting compounds such as phenolics, flavonoids and antioxidants in the persimmon fruit.

Meanwhile, Mr Mahmood along with Horticulture team at ECU have identified a gap for a review specifically the implications of MeJA as a preharvest spray application on development of colour and quality in fruit crops. They spent over six months and complied a comprehensive review.

This review paper reflects the effects of preharvest MeJa application on advancing fruit colour and improving the phytochemical quality of harvested fruit, while also displaying a potential to alleviate chilling injury in cold-stored fruits