ABSTRACT
Currently, southern Minas Gerais (MG) state is an important producer of different olive tree (Olea europaea L.) cultivars because, in this region, the plants can differentiate the buds to produce flowers and fruit. To stimulate the rooting of cuttings, the synthetic hormone indole-3-butyric acid (IBA) at a concentration of 3 g L−1 is used commercially. However, few studies have investigated arbuscular mycorrhizal fungi (AMF), isolated or combined with rhizobacteria, as a biotechnological tool to produce hormones that function in the rooting of olive tree cuttings. The aim of this study was to evaluate the capacity of different AMF species (Rhizophagus clarus, Gigaspora rosea, or Acaulospora scrobiculata), combined or not with IBA or rhizobacteria, to promote the rooting of three olive tree cuttings (Arbequina, Grappolo 541, and Maria da Fé) with potential for cultivation in this region. For this, three experiments were conducted at the Experimental Farm of EPAMIG in Maria da Fé (MG), and the rooting potential of the olive tree cuttings inoculated with I) AMF, II) AMF combined with increasing doses of IBA, and III) AMF combined with three isolates of rhizobacteria was evaluated. The inoculation of olive tree cuttings of cultivars Arbequina, Grappolo 541, and Maria da Fé with Rhizophagus clarus, Gigaspora rosea, or Acaulospora scrobiculata combined or not with IBA or rhizobacteria did not significantly promote rooting. Alternative forms of rooting olive tree cuttings are still a challenge, and further studies for standardizing methodologies and experimental conditions are required.
Subject(s)
Plant Roots , Mycorrhizae , OleaABSTRACT
ABSTRACT: Aiming the selection of rootstocks to produce seedlings, the objective of this study was to quantify the seminiferous propagation in chestnut seeds, with or without incisions. Nine cultivars were used ('Ibuki', 'Isumo', 'Kinshu', 'Moriwase', 'Okuni', 'Senri', 'Taishowase', 'Tamatsukuri' and 'Tiodowase') and two selections ('KM-1' and 'KM-2') of hybrid chestnut trees (Castanea crenata x Castanea sp.). An incision was held in half of chestnuts and the other half remained intact. Percentage of germination, emergence and root length were quantified. The germinated nuts were transplanted and were quantified the diameter and height of seedlings. Then, the chestnut selections 'KM-2' and 'Jacutinga' were grafted by the cleft grafting method, and were quantified the percentage of sprouting, besides the diameter and height of grafts. Incisions increase the germination and seedling emergence in most cultivars and selections. 'Taishowase' and 'Tamatsukuri' stood out over the others to germination, growth of the rootstocks.
RESUMO: Visando a seleção de porta-enxertos para a produção de mudas, o objetivo do trabalho foi quantificar a propagação seminífera em castanhas com ou sem a realização de incisões. Foram utilizadas nove cultivares ('Ibuki', 'Isumo', 'Kinshu', 'Moriwase', 'Okuni', 'Senri', 'Taishowase', 'Tamatsukuri' e 'Tiodowase') e duas seleções ('KM-1' e 'KM-2') de castanheira híbridas (Castanea crenata x Castanea sp.). Em metade das castanhas, realizou-se uma incisão e a outra metade das castanhas permaneceu intacta. Foram quantificadas a porcentagem de germinação, emergência e o comprimento das raízes. As castanhas germinadas foram transplantadas onde se quantificou o diâmetro e a altura das mudas e ao final, a massa seca da parte aérea. Em seguida foram enxertadas pelo método de garfagem as seleções de castanheira 'KM-2' e 'Jacutinga', se quantificando a porcentagem de brotação, além do diâmetro e altura dos enxertos. Concluiu-se que as incisões aumentam a germinação e a emergência das plântulas, na maioria das cultivares e seleções. 'Taishowase' e 'Tamatsukuri' se destacam em relação as demais quanto a germinação e crescimento dos porta-enxertos.