Grafting Effects on Tomato Growth Rate, Yield and Fruit Quality under Saline Irrigation Water A. Balliu, G. Vuksani S. Kaçiu T. Nasto and L. Haxhinasto University of Pristina Agricultural University of Tirana Pristina Tirana Kosovo Albania Keywords: tomato, grafting combinations, growth rate, yield, fruit quality, saline irrigation water Abstract The grafting influences on growth rate and harvested yield under plastic greenhouses, compared to common commercial seedlings, were estimated in several combinations of ‘Charlotte F 1 ’ and ‘Bona F 1 ’ tomato cultivars (Lycopersicon esculentum L.) with ‘Energy’, ‘Prospero’ and ‘Cyndia’ rootstock cultivars (Lycopersicon spp). Grafting response to growth, yield and fruit characteristics under the saline irrigation water conditions were simultaneously estimated in a single grafting combination (Cyndia x Charlotte). Natural soil and Klasmann grow bags were respectively used as substrate in the first and the second experiment. Commercial cultivation practices were used in the first experiment and nutrient solutions composed by NPK, respectively; 200, 40 and 250 mg L -1 , were applied at the second one. Different levels of NaCl (0,0; 2,5 and 5,0 mM), were added in. Specific rootstock: scion combinations have demonstrated significant differences among each other, regarding to plant growth rate and harvested yield. No significant increase of plant yield, compared to the no grafted plants was usually observed. A depression effect even, was present in some cases. NaCl addition in the irrigation water was responsible for the significant reduction of plant growth rate and yield, but meantime, an increase in fruit dry matter, soluble solids and ascorbic acid content was evident. Thanks to grafting, a higher growth rate was promoted, and bigger fruits, more rich in soluble solids and ascorbic acids were developed compared to no grafted plants. INTRODUCTION It is a well known fact that the successful production of vegetable crops relies on the use of high quality transplants. Vegetable production using grafted seedlings has become a common practice in many parts of the world. It has been improved over the last decade, thanks to the introduction of new techniques and materials. Grafted vegetables increased in plastic greenhouses and high tunnels because of the stressful conditions from late fall to early spring such as low light intensity, high humidity, and low temperature (Lee, 2003). These conditions cause various physiological as well as pathological disorders leading to severe crop loss. The main reason for vegetable grafting is thus to improve their adaptation to stresses (Leonardi and Romano, 2004). Uptake, as well as the translocation of various substances such as ions, photosynthates, plant hormones, alkaloids, and viruses, can be influenced by rootstocks or by grafting. Since one of the basic purposes for grafting is the utilization of the vigorous root systems of the rootstocks, grafted plants usually show increased uptake of water and minerals as compared to the self-rooted plants. This enhanced uptake of minerals appeared to be closely associated with the activity of enzymes responsible for absorption. Plants with vigorous root systems produce more cytokinins and the yield increase induced by a vigorous rootstock is closely associated with the amount of cytokinins in the ascending xylem sap (Lee and Oda, 2003). Grafting combination may determine different plant vigor expressed through variations in growth, yield and product quality (Romano and Pratore, 2001). The 1161 Proc. IS on Greensys2007 Eds.:S. De Pascale et al. Acta Hort. 801, ISHS 2008