Selecting a new citrus rootstock for Satsuma (Citrus unshiu Marc.) in the Syrian coast

A completely randomized blocks design experiment was conducted for eleven years at Siano research station, Jableh, Latakia, Syria in order to select a new rootstock for satsuma (Citrus unshiu Marc.) cv. ‘St-Jean’ plantations. Sour orange, Citrumelo 1452, Citrumelo 4475, Rangpur lime, Carrizo citrange, Troyer citrange, Trifoliate orange “Robidoux” and Volkamer lemon were used as rootstocks. Yield (kg/tree), trunk cross-sectional area (cm2) above and below grafting area, fruit weight (g), peel thickness (mm), juice content (%), titratable acidity (TA%), and total soluble solids (TSS%) were estimated. Depending on trunk cross-sectional areas, morphological compatibility was high between Satsuma and Rangpur lime, Sour orange, and Volkamer lemon, while it was low with Citrumelo 1452, 4475, and Trifoliate orange. Trees budded onto Sour orange gave the highest canopy volume, while trees buddied onto Trifoliate orange gave the lowest. On average, Satsuma buddied onto Citrumelo 1452 gave the highest yield (174 kg/tree), followed by those buddied onto Troyer citrange (167 kg/tree), Citrumelo 4475 (165 kg/tree), Volkamer lemon (163 kg/tree), and Sour orange (152 kg/tree) without significant variation among them. Canopy efficiency (kg/m3) was higher in trees buddied onto Trifoliate orange, while it was lower in those grafted on Sour orange. Mean fruit weight was close among all treatments, However, it was the lowest using Sour orange and Carrizo citrange, while no significant variations were found regarding peel thickness or juice content. No significant variations were found in TSS% between Citrumelo 4475, 1452, Carrizo, Troyer citrange, or Sour orange, while TSS% decreased significantly using Rangpur, Trifoliate, and Volkamer lemon rootstocks. Additionally, fruit titratable acidity and maturity index (TSS/TA) were not influenced by rootstock type. Due to its superiority in many of the studied characteristics, Citrumelo 1452 can be suggested as a suitable rootstock for satsuma in the studied area and areas with similar conditions as an alternative to Sour orange.