ADIL H. ABDELMAGEED1, NAZIM GRUDA2, BERND GEYER2
1University of Khartoum, Department of Horticulture, Sudan
2Humboldt-Universität zu Berlin, Department of Vegetable Crops, Germany
Tomato (Lycopersicon esculentum MILL.) is a warm season vegetable crop with an optimum temperature for production of 28/22 ºC (day/night). Heat stress is a major environmental stress that limits tomato production during summer under arid conditions. A variety of control measures and techniques including cultural practices in the field have been tested at the University of Khartoum in Sudan for tomato production under high temperature. Additionally grafting techniques have been used with heat sensitive and heat tolerant cultivars and with heat sensitive tomato cultivars as scion and eggplant cultivars as rootstock.
The objective of this study is to examine if there is any positive effect of grafting on the vegetative and reproductive development in tomato plants. Further, grafting effects were investigated on tomato plants under heat stress conditions.
The heat tolerant tomato cultivar `Summer set' and the eggplant cultivar `Black beauty' as rootstock as well as the less heat tolerant tomato cultivar `UC 82-B' as scion were selected. Plants were grown under two temperature regimes 30/22 ºC and 38/27 ºC (day/night) in plant growth chambers at the Department of Vegetable Crops, Institute for Horticultural Sciences, Faculty of Agriculture and Horticulture, Humboldt University of Berlin. The experiments were set up in a complete randomised design with five plants for each treatment. The following characteristics were recorded: leaf area, fresh and dry weight of leaves and stem, fresh and dry weight of roots, number of clusters, number of flowers, and the number of pollen grains per microscopic field. In addition chlorophyll fluorescence and electric conductivity were measured, suggested as a screening technique for heat tolerance.
Significant differences were encountered between treatment UC 82-B/Black beauty and UC 82-B under 38/27 ºC for chlorophyll fluorescence, electric conductivity and other vegetative and reproductive parameters. On the whole, grafting may have slightly positive effects on tomato production under high temperature conditions.
Keywords: Arid conditions, grafting, heat stress, tomato