Tree Canopy Volume and Leaf Mineral Nutrient Concentrations of 'Redblush' Grapefruit on Twelve Rootstocks 1

Abstract

Tree growth, leaf fresh weight, dry matter and mineral nutrient concentrations and their relationships with yield in ‘Redblush’ grapefruit ( Citrus paradisiMacf.) on twelve rootstocks under the desert conditions of southwest Arizona were studied over several years. Trees on Volkamer lemon ( C. limonBurm. f.), Oklawaha sour orange ( C. aurantiumL.), rough lemon ( C. jambhiriLush) and Carrizo citrange [ C. sinensis(L.) Osbeck x Poncirus trifoliata(L.) Raf.] had large canopy volumes and highe yields while those on Savage citrange [ C. sinensis(L.) Osbeck x P trifoliata(L.) Raf.], Ichang pummelo ( C. ichangensishyb.), Cleopatra mandarin ( C. reticulataBlanco.), Swingle citrumelo ( C. paradisix P. trifoliata) and macrophylla (Alemow) ( C. macrophyllaWester) were in low yield and small canopy group. ‘Redblush’ grapefruit trees on Palestine sweet lime ( C. limettiodesTan.) were in the high yielding group in spite of their small canopy volume. Trees on Savage citrange had the highest leaf percent dry matter, while those on Volkamer lemon had the lowest. Leaves of trees on macrophylla had the highest levels of N, Cu, Mn and Fe, but the lowest levels of Ca and Mg. Trees on all citranges and Swingle citrumelo had low leaf N, and those on citranges also had low leaf Zn and Mn. ‘Redblush’ grapefruit trees on Volkamer lemon and Ichang pummelo had the highest leaf Zn.