Determination of Optimal Growing Degree Days and Cultivars of Kimchi Cabbage for Growth and Yield during Spring Cultivation under Shading Conditions

Abstract

This study determined the optimal growing degree days (GDD) and cultivars of Kimchi cabbage (Brassica rapa L. ssp. pekinensis) for growth and yield during spring cultivation under shading condition. There were nine treatments, and the experiments were conducted with three GDD levels (899, 924, and 961) and three cultivars (‘Chungwang’, ‘Cheongna’, and ‘Cheongok’) under shading conditions. The process-based model of Kimchi cabbage was applied for growth and yield prediction using meteorological data regarding light, temperature, wind, precipitation, and humidity in several regions. The number of leaves of ‘Chungwang’ Kimchi cabbage was greater than that of ‘Cheongna’ and ‘Choengok’ at all planting times. Most of the growth parameters were highest in the delayed transplanting treatment than in the other transplanting times. ‘Chungwang’ Kimchi cabbage was less sensitive to high temperature during spring cultivation than the other cultivars. GDD 924 was the most optimal time to harvest under the shading condition. GDD 750-870 is considered an appropriate harvest time in the primary production regions during the spring cultivation season. If shading is performed in these regions, constant production may be possible, thus, alleviating damage from high temperature.