Improvement of early growth of tomato and eggplant grafted cuttings by warming of graft union at beginning of low temperature storage

• Published in: Acta horticulturae no. 923; pp. 255 - 260
• Main Authors: Shibuya, T, Shimizu-Maruo, K, Kawara, T, Tsuchiya, K, Douzono, M
• Format: Journal Article
• Language: English
• Published: International Society for Horticultural Science 01.01.2011
• Subjects: acclimation; eggplants; greenhouses; growers; labor; lamps; planting; rooting; rootstocks; scions; soaking; storage temperature; storage time; tomatoes
• ISSN: 0567-7572
• DOI: 10.17660/ActaHortic.2011.923.38

The grafted cuttings of tomato and eggplant were warmed from the basal end to the graft union at the beginning of low temperature storage to improve develop-ment of their graft-union and early growth after planting. The scions were grafted onto the rootstock cuttings using the splice-grafting method. Then the grafted cuttings were soaked in nutrient solution (held at 27°C) from the basal end to the graft union for 2 d (tomato) or 3 d (eggplant) at the beginning of 14 days of low temperature (9°C) storage. White fluorescent lamps provided continuous illumina¬tion at a photosynthetic photon flux density of 10 micromol∙m-2∙s-1. During the remainder of the storage period, the cuttings were stored with soaking only the basal end of the rootstock in non-warmed nutrient solution. Non-warmed cuttings were also stored for 14 d. The tensile strengths of the graft-union in the warmed cuttings were 2.0 and 1.7 times those in non-warmed tomato and eggplant cuttings, respectively, at the end of storage. When the tomato and eggplant grafted-cuttings were grown in a greenhouse for 5 and 7 d, respectively, after planting, the relative growth rates of the warmed cuttings were 1.2 and 2.3 times those of non-warmed and non-stored cuttings, respectively, in tomato, and were 1.5 and 2.1 times those in eggplant. The warming technology would reduce labor requirements of transplant growers during acclimatization because it allows the transplanting work to be spread out over a longer period and improves the development of graft union and the quality of the rooting site during and after storage.