JIA-2019-11

Journal of Integrative Agriculture 2019, 18(11): 2521–2533 RESEARCH ARTICLE Available online at www.sciencedirect.com ScienceDirect Modelling seedling development using thermal effectiveness and photosynthetically active radiation ZHOU Tian-mei 1, 5* , WU Zhen 1* , WANG Ya-chen 1 , SU Xiao-jun 2 , QIN Chao-xuan 3 , HUO He-qiang 4 , JIANG Fang-ling 1 1 College of Horticulture, Nanjing Agricultural University, Nanjing 210095, P.R.China 2 Institute of Vegetables, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R.China 3 Machinery Institute, Nanjing University of Science and Technology, Nanjing 210094, P.R.China 4 Mid-Florida Research and Education Center, University of Florida, Apopka 32703, USA 5 Taicang Agricultural Technology Extension Center, Taicang 215400, P.R.China Abstract Seedling quality is a prerequisite for successful field performance and therefore influences crop yields. Temperature and illumination are two major factors affecting seedling quality during nursery propagation. Suboptimal temperature or light of nurseries generally result in leggy or weak seedlings and great economic loss. However, production of healthy seedlings is challenging due to the lack of knowledge in systemic management of nursery environments. In this study, we have established simulation models to predict how temperature and illumination coordinately influence the growth of tomato and cabbage seedlings. Specifically, correlation between seedling quality characteristics (root-shoot ratio, G value (growth function: defined as ratio of whole plant dry weight to days of seedling), healthy indexes) and TEP (thermal effectiveness and photosynthetically active radiation) were explored to establish the models, which were validated with independent test data. Our results suggested that the curve of healthy index 1 (HI1) and TEP fitted well with high coefficient of determination ( R 2 ) in both species, indicating that the model is highly reliable. The HI1 simulation models for tomato and cabbage are HI1=0.0009e 0.0308TEP −0.0015 and HI1= 0.0003e 0.0671TEP −0.0003, respectively, which can be used for predicting vigors of tomato and cabbage seedlings grown under different temperature and light conditions. Keywords: tomato, cabbage, simulation model, thermal effectiveness and photosynthetically active radiation, healthy index, G value 1. Introduction Tomato ( Solanum lycopersicum ) and cabbage ( Brassica oleraca L. var . capitata L.) are the world’s most important vegetable crops, and seedling transplantation has been widely adopted for its uniformity and high vigor. During seedling propagation in nurseries, seedling quality greatly influences subsequent field performance, such as survival, growth, yields, and quality (Mattsson 1996; Wang et al . Received 26 December, 2018 Accepted 06 May, 2019 ZHOU Tian-mei, E-mail: 370724508@qq.com; Correspondence JIANG Fang-ling, Tel/Fax: +86-25-84396251, E-mail: jfl@njau. edu.cn * These authors contributed equally to this study. © 2019 CAAS. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/) . doi: 10.1016/S2095-3119(19)62671-7