Use of maturity sorting and reducing ethylene with potassium permanganate to enhance marketing of tomatoes in Laos at ambient tropical temperatures

Demand for tomato is increasing in Laos but marketing options are limited due to ripening during transit. This study quantified changes in fruit ripening during commercial transit to the major urban market in Laos, and investigated extension in market life achieved by inclusion of an ethylene absorbent into packages of green fruit. Ripening during the transport tomatoes of mixed maturity in the same package from to Vientiane was assessed by scoring fruit colour at harvest and arrival at the market. An intervention trial was then conducted where green tomatoes were packed with an ethylene absorbent and ripeness assessed over seven days at ambient temperature.  During the 24-hour journey of 750 km from farm to urban market, the mean colour score increased from 2.4 to 3.5 with the proportion of green fruit (score 1) decreasing from 35 % at harvest to 5 % at Vientiane.  In the trial where tomatoes were sorted so only green (score 1) and breaker (score 2) fruit were packed in containers, the inclusion of sachets of a low-cost potassium permanganate ethylene absorbent significantly delayed ripening - 75% of fruit remained green after 7 days storage which was double that in control boxes.  Findings need to be confirmed on larger shipments to a range of markets. Originality/Value: On-farm sorting for maturity coupled with the marketing of ripening fruit on local markets and green fruit held in reduced ethylene to more lucrative markets can increase the economic situation for Lao farmers.