Valencia sweet orange trees budded onto citrandarins and others trifoliate hybrids rootstocks from the USDA Horticultural Research Laboratory, Fort Pierce, Florida, were planted in 1988 on a sandy textured Oxisol in São Paulo State, Brazil, and managed without irrigation. Tristeza and blight diseases are endemic in this area. Trees of Sunki x English (1.628), Cleopatra x Rubidoux (1.660), Cleopatra x English (710), Cleopatra x Swingle (715) and Rangpur lime x Carrizo citrange (717), produced the highest cumulative yields in the first five crops (1991-1995). The first three rootstocks induced the highest crops in the last three years. Carrizo and Troyer citranges had the lowest productions in all years except in 1994. None of the trees showed symptoms of tristeza or blight diseases. Seedlings of these rootstocks were compared for resistance to Phytophthora parasitica inoculations. The citrandarins Cleopatra x Swingle (1.587), Cleopatra x Trifoliate (1.574), Cleopatra x Rubidoux (1.600), Clementine x Trifoliate (1.615) and Rangpur lime x Carrizo citrange (717), were significantly more resistant than the Cleopatra x Christian (712), Sunki x English (1.628), Cleopatra x Swingle (715) and Cleopatra x English (710).
Citranges; Sunki hybrids; Cleopatra hybrids; Phytophthora
