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2025 Vol.34, Issue 4 Preview Page

Original Articles

Optimal Air Temperature for Producing High-Quality Grafted Watermelon Seedlings in a Plant Factory System

식물공장 시스템에서 고품질 수박 접목묘 생산을 위한 최적 대기온도

Young Je Kim1†
,
Se Hun Ju2†
,
Eun Ji Kim2
,
Hyunseung Hwang3
,
Haeyoung Na4*
김 영제1†
,
주 세훈2†
,
김 은지2
,
황 현승3
,
나 해영4*
1Graduate Student, Department of Horticultural Science, Graduate School of Mokpo National University, Muan 58554, Korea
2Graduate Student, Interdisciplinary Program of Development and Utilization of Biological Resources, Graduate School of Mokpo National University, Muan 58554, Korea
3Professor, Department of Horticulture and Breeding, College of Life Science and Biotechnology, Gyeongkuk National University, Andong 36729, Korea
4Professor, Department of Horticulture and Forestry, College of Life and Medical Sciences, Mokpo National University, Muan 58554, Korea
1국립목포대학교 일반대학원 원예학과 대학원생
2국립목포대학교 일반대학원 생명자원개발이용학협동과정 대학원생
3국립안동대학교 스마트원예과학과 교수
4국립목포대학교 생명·의과학대학 원예산림학부 교수
*Corresponding Author
†These authors contributed equally to this work.
31 October 2025. pp. 393-400
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Abstract

This study aimed to determine the optimal air temperature for producing high-quality grafted watermelon (Citrullus lanatus) seedlings in a plant factory–based seedling production system. Grafted seedlings, with ‘DongjangGun’ as the rootstock and ‘SantaKkul’ as the scion, were cultivated for 21 days under three daytime air temperature treatments of 23°C, 28°C, and 33°C with a constant nighttime temperature of 18°C. Growth traits including plant height, root length, leaf number, leaf area, stem diameter, and biomass, as well as seedling quality indices such as top-to-root ratio, compactness, and crop growth rate (CGR), were evaluated at 7, 14, and 21 days after grafting. Seedling growth responses were strongly influenced by temperature. Higher temperatures promoted stem elongation, with seedlings at 33°C showing the tallest height but also exhibiting excessive elongation and reduced stem thickening, which are indicative of lower seedling quality. In contrast, seedlings grown at 28°C exhibited greater leaf area, thicker stems, and a more balanced allocation of shoot and root biomass. Seedling quality indices also confirmed that compactness, T/R ratio, and CGR were most favorable under 28°C by 21 days. Collectively, these findings demonstrate that while both 28°C and 33°C promoted vigorous growth, only 28°C supported sturdy morphology and balanced biomass allocation. Therefore, 28°C can be considered the optimal daytime air temperature for grafted watermelon seedling production in plant factory systems, providing a basis for stable year-round seedling production and improved environmental control strategies.

Keywords
Air temperature
Biomass allocation
Compactness
Crop growth rate (CGR)
Top-to-root ratio (T/R ratio)

본 연구는 식물공장형 육묘시스템에서 고품질 수박(Citrullus lanatus) 접목묘 생산을 위한 최적 대기온도를 규명하기 위해 수행되었다. 대목은 ‘동장군’(DongjangGun), 접수는 ‘산타꿀’(SantaKkul)을 이용하여 접목묘를 생산하였으며, 야간온도 18°C를 일정하게 유지한 상태에서 주간 대기온도를 23°C, 28°C, 33°C로 처리하여 21일간 재배하였다. 접목 후 7, 14, 21일에 초장, 근장, 엽수, 엽면적, 경경, 생체중 및 건물중과 같은 생육 지표뿐만 아니라, T/R율, 충실도(compactness), 생장속도(CGR)와 같은 묘 품질 지표를 평가하였다. 그 결과, 묘의 생육 반응은 온도에 의해 크게 영향을 받았다. 고온 조건에서는 초장이 유의적으로 증가하였으며, 33°C 처리구에서 가장 길게 나타났으나 과도한 신장과 경경 감소가 동반되어 묘 품질이 저하되었다. 반면 28°C 처리구에서는 엽면적과 경경이 가장 크고, 지상부와 지하부 간의 생체중 배분도 균형적으로 나타났다. 또한 묘 품질 지표에서도 접목 후 21일에 28 °C 처리구에서 T/R율, 충실도, 생장속도가 가장 우수하였다. 종합하면, 28°C와 33°C 모두 생육을 촉진하였으나, 28°C 처리구에서만 묘의 형태적 안정성과 생체중의 균형적 분배가 확보되었다. 따라서 식물공장형 육묘시스템에서 수박 접목묘 생산의 최적 주간 대기온도는 28°C로 판단되며, 이는 연중 안정적인 묘 생산과 환경제어 전략 수립을 위한 기초 자료로 활용될 수 있을 것이다.

키워드
대기온도
생장속도
생체중 배분
충실도
T/R율
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Information
  • Publisher :The Korean Society for Bio-Environment Control
  • Publisher(Ko) :(사)한국생물환경조절학회
  • Journal Title :Journal of Bio-Environment Control
  • Journal Title(Ko) :생물환경조절학회지
  • Volume : 34
  • No :4
  • Pages :393-400
  • Received Date : 2025-09-24
  • Revised Date : 2025-09-29
  • Accepted Date : 2025-10-02
  • DOI :https://doi.org/10.12791/KSBEC.2025.34.4.393
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