Vegetative rescue potential of Brazil nut through epicormic shoots on detached branches

Obtaining juvenile material may favor the clonal propagation of Brazil nut, Bertholletia excelsa. We aimed to assess the emission of epicormic shoots on detached branches of Brazil nut trees as a function of the mother tree and branch diameter, in order to provide juvenile material for use in clonal multiplication. The experimental design was completely randomized in a 6 (mother trees) x 3 (stem diameter: < 20 20-40 and 40-80 mm) factorial design, with four replicates. Every five days the number of shoots emitted was counted and the sprouting speed index and average sprouting time were calculated. The number of epicormic shoots and the sprouting speed index were dependent on the interaction between mother tree and branch diameter. Branches with larger diameter (20-40 and 40-80 mm) showed higher potential for obtaining propagules for use in Brazil nut clonal multiplication (cutting, grafting and in vitro cultivation). (AU)

Vegetative rescue potential of Brazil nut through epicormic shoots on detached branches / Potencial de resgate vegetativo da castanha-do-brasil a partir de brotações epicórmicas de ramos destacados

Obtaining juvenile material may favor the clonal propagation of Brazil nut, Bertholletia excelsa. We aimed to assess the emission of epicormic shoots on detached branches of Brazil nut trees as a function of the mother tree and branch diameter, in order to provide juvenile material for use in clonal multiplication. The experimental design was completely randomized in a 6 (mother trees) x 3 (stem diameter: 20 20-40 and 40-80 mm) factorial design, with four replicates. Every five days the number of shoots emitted was counted and the sprouting speed index and average sprouting time were calculated. The number of epicormic shoots and the sprouting speed index were dependent on the interaction between mother tree and branch diameter. Branches with larger diameter (20-40 and 40-80 mm) showed higher potential for obtaining propagules for use in Brazil nut clonal multiplication (cutting, grafting and in vitro cultivation).(AU)

A obtenção de material juvenil pode favorecer a propagação clonal da castanha-do-Brasil, Bertholletia excelsa. Objetivou-se avaliar a emissão de brotações epicórmicas em ramos destacados de castanheira, em função da planta-matriz e do diâmetro dos mesmos, visando disponibilizar material juvenil que possa ser utilizado na multiplicação clonal da espécie. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 6 (plantas-matriz) x 3 (diâmetros do ramo: 20, 20-40 e 40-80 mm), com quatro repetições. A cada cinco dias, o número de brotos emitidos foi contado e o índice de velocidade e tempo médio de brotação foram calculados. O número de brotações epicórmicas e o índice de velocidade de brotação foram dependentes da interação entre plantas-matriz e diâmetro do ramo. Ramos de maior diâmetro (20-40 e 40-80 mm) mostraram maior potencial para obtenção de propágulos para uso na multiplicação clonal (estaquia, enxertia e cultivo in vitro) da castanha-do-Brasil.(AU)

Rooting of eucalypt cuttings as a problem-solving oriented model in plant biology.

Species of Eucalyptus are some of the most planted trees in the world, providing fiber, cellulose, energy, and wood for construction and furniture in renewable fashion, with the added advantage of fixing large amounts of atmospheric carbon. The efficiency of eucalypts in forestry relies mostly on the clonal propagation of selected genotypes both as pure species and interspecific hybrids. The formation of new roots from cambium tissues at the base of cuttings, referred to as adventitious rooting (AR), is essential for accomplishing clonal propagation successfully. AR is a highly complex, multi-level regulated developmental process, affected by a number of endogenous and environmental factors. In several cases, highly desirable genotypes from an industrial point of view carry along the undesirable trait of difficulty-to-root (recalcitrance). Understanding the bases of this phenotype is needed to identify ways to overcome recalcitrance and allow efficient clonal propagation. Herein, an overview of the state-of-the-art on the basis of AR recalcitrance in eucalypts addressed at various levels of regulation (transcript, protein, metabolite and phenotype), and OMICs techniques is presented. In addition, a focus is also provided on the gaps that need to be filled in order to advance in this strategic biological problem for global forestry industry relying on eucalypts.