Horticultural Science and Technology 원예과학기술지 ISSN:1226-8763(Print) 2465-8588(Online)

The Korean production of highly valuable horticultural crops is less than 50% of the production in The Netherlands. The production in Korea can be improved by yield gap analyses between a Dutch and a Korean grower. Fruit set, number of fruits, production of sweet pepper, and climate data of a Dutch commercial grower were measured and compared with a Korean commercial grower. Greenhouse type and cultivar were same in both countries. The Korean grower produced faster and more fruits after planting. However, with the increase in daily radiation later in the growing season, the Dutch grower harvested more sweet peppers per week, which results in a higher final production. Consequently, the difference in yield between growers was 10 kg·m^-2. Low radiation along with large leaves and the relatively higher number of fruits for the young plants resulted in a low source-to-sink ratio (SSR), which causes abortion of reproductive organs. The fruit load varied between the two countries; however, it does not explain the factors limiting the yield. SSR can predict the onset of fruiting, and an SSR above 0.5 suggested fruit onset. An SSR below this threshold value indicates light limitations. The SSR limits the fruit set, possibly due to high fruit loads and high vegetative sink strength. In the last part of the growing season, other factors could have played a role in the lower fruit set, since the SSR was mainly above 1. To improve yield, the Korean grower needs to know how to manipulate the vegetative and generative plant balance based on weather conditions, irrigation management, and plant growth and developmental rate.