Selecting the Best Citrus Rootstock for Young `Valencia' Orange Trees Under Soil Salinity Stress Conditions

Abstract

This study was conducted during 2002 and 2003 seasons to select the best citrus rootstocks for young `Valencia' orange trees grown under soil salinity stress. Six citrus rootstocks namely Volkamer lemon, Cleopatra mandarin, Troyer citrange, Rough lemon, Egyptian lime, and Sour orange were tested. Four soil salinity levels, namely, 0.0%, 0.1%, 0.2%, and 0.4% were examined. Results showed that growth criteria, plant pigments and percentages of N, P, and K in the leaves of `Valencia' orange onto all citrus rootstocks tended to reduce with raising soil salinity. The harmful effects imposed by soil salinity was `Valencia' orange on Volkamer lemon, Cleopatra mandarin Troyer citrange, Rough lemon, Egyptian lime, and Sour orange, in asending order. Results proved the superiority of Volkamer lemon, Cleopatra mandarin, and Trouyer citrange rootstocks for `Valencia' orange transplants grown under salinity conditions as compared to the other rootstocks. `Valencia' orange on such promising rootstocks could tolerate soil salinity until 0.20% without adverse effects on growth of transplants. Sour orange rootstock seems to be the lowest suitable stock for `Valencia' orange tansplants grown under soil salinity conditions.