Performance of 'Nova' mandarin on eleven rootstocks in Cyprus

Tree size, yield, yield efficiency, fruit quality and leaf nutrients of 'Nova' mandarin (Citrus reticulata Blanco x (C. paradisi Macf. x C. reticulata)) on 11 rootstocks were evaluated under Cyprus conditions. Cumulative yield over the 11-year production period was highest on Palestine sweet lime rootstock (C. limettioides Tan.), followed by that on rough lemon (C. jambhiri Lush.), sour orange (C. aurantium L.), Volkamer lemon (C. volkameriana Ten. and Pasq.) and Estes rough lemon, although there were no significant differences among these rootstocks. Cumulative yields on Carrizo and Yuma citranges (C. sinensis cv. Washington navel x Poncirus trifoliata (L.) Raf.) were next in order, followed by those on Rangpur (C. limonia Obs.), C. taiwanica, Troyer citrange and Swingle citrumelo (C. paradisi Macf. x P. trifoliata). The largest trees were on sour orange, rough lemon and Palestine sweet lime, and the smallest on Yuma and Carrizo citranges, Swingle citrumelo and Rangpur. Yield efficiency was highest on Carrizo citrange, whereas other rootstocks had similar yield efficiencies. Rootstock affected fruit size and weight, rind thickness, juice content, Brix, total acids and Brix:acid ratio. Leaf analysis showed significant differences among rootstocks in the concentration of 10 out of 12 elements. Overall, results so for showed that Carrizo citrange and Volkamer lemon are the most promising for replacing the sour orange rootstocks which is used commercially in Cyprus but which is highly susceptible to tristeza. (C) 2000 Elsevier Science B.V. All rights reserved.