Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Vegetable

This study aims to determine the efficiency of grafting to improve growth and production of tomato (Solanum lycopersicum.) under salinity stress condition. A commercial tomato hybrid (cv. Bark) and eight wild tomato accessions were evaluated at molecular, physiological and agronomic levels. At the molecular level, two powerful gene-targeting marker systems (Conserved DNA-Derived Polymorphism; CDDP and Start Codon Targeted Polymorphism; SCoT) were employed. Besides, Bark cv. was grafted as a scion onto the roots of the four tomato genotypes as stocks.The rootstocks effect was evaluated by growing plants at two NaCl concentrations plus the control (0, 100, and 200 mM NaCl). Plant vegetative growth, fruit yield, fruit quality, and minerals content in leaves were determined. In addition, several antioxidants, hormones, and proline were evaluated to better understand of the physiological changes induced by salinity and grafting.Our results showed that grafting enhanced plant shoots and roots growth (plant height, number of branches, plant fresh weight, root length, and root fresh and dry weight), fruit yield (total yield, number and weight of fruits), fruit quality (Vitamin C, firmness, and total soluble solids) in Bark on most tested rootstocks. In conclusion, our consistent results from the three approaches (molecular, physiological and agronomical) revealed that the five genotypes (LA1995, LA2711, LA2485, LA3845, and Bark) were found to be grouped and exhibit better performance under salinity stress conditions. Furthermore, grafting could be a low-cost alternative method to improve salt tolerance in tomato sensitive genotypes

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