Effects of Citrus Rootstocks on Quantity and Quality Fruit Parameters of  Washington Navel Orange Selected Strains

This experiment was conducted to determine the best rootstock for ‘Washington Navel’ orange. Nine selected strains of ‘Washington Navel’ were budded on three rootstocks including; Sour orange (Citrus aurantium), Citrange [(Poncirus trifoliata (L.) Raf × C. sinensis (L.) Osbeck)] and Trifoliate orange (Poncirus trifoliata (L.) Raf) in Astara Research Station. This experiment was carried out as a factorial in a randomized complete block design with 27 treatments and seven replications for five years. Results showed that cumulative yield per tree, yield efficiency and TSS were significantly higher on the Trifoliate orange rootstock. The largest cumulative yield per tree, and yield efficiency were observed on the B, F, I and E strains and the lowest were observed on D strain. The higher yield per tree was on the B, F, I and E strains when trees were budded onto the Trifoliate orange rootstock. The lowest alternate bearing index observed on E strain on Citrange and Poncirus rootstocks. The lowest yield and the greatest alternate bearing index were recorded C strain that budded onto the Citrange rootstock. Height, width, and canopy volume of trees were not affected by treatments. The greatest trunk to scion ratio was on C strain onto the Trifoliate orange and the lowest ratio was on G strain on Sour orange. Cluster analysis based on total measured treats was grouped strains in two main clusters and B, F, I and E strains were in one group. The combination of B, F, I and E strains on Trifoliate orange rootstock is advisable in this area.