Growth and quality of australian cedar saplings originated from different multiclonal minigarden systems

Abstract

Forestry researchers often evaluate minicutting vegetative propagation of Australian cedar (Toona ciliata) as a viable technique for this species. However, the adoption of minigarden systems for commercial propagation still requires viability and quality testing of saplings produced after multiple harvests. In the present work, we evaluate survival, growth, and quality of Australian cedar saplings grown from minicuttings originating from multiple harvests of ministumps planted in gutter or tube systems. Experiments were conducted in a greenhouse using a completely randomized design with a 2 × 4 factorial treatment structure (two minigarden systems and four minicutting harvests). For the gutter system, six minicutting harvests were performed 50, 86, 115, 149, 177 and 212 days after planting ministumps, whereas for the tube system, four harvests were performed 115, 149, 177 and 212 days after planting ministumps. At the end of each sapling production cycle (105 days after each minicutting harvest), saplings were evaluated for survival, foliar area, dry mass of aerial parts, number and length of adventitious roots, dry mass of the root system, height to diameter ratio, ratio between the dry mass of aerial parts and dry mass of root system, and Dickson's Quality Index. Sapling survival was not affected by minigarden system, except for a reduction observed in fourth cycle saplings from the tube system. Sapling quality was also similar between systems. However, sapling growth potential decreased with production cycle, indicating that ministumps lose vigor with multiple harvests. Key words: Minicuttings. Sapling quality. Toona ciliata. ResumoA propagação vegetativa por miniestaquia do cedro australiano (Toona ciliata) tem sido alvo de pesquisas, mostrando ser uma técnica viável para esta espécie. Entretanto, para a adoção de sistemas de minijardins em canaletão e em tubetes na propagação comercial, ainda é necessário testar a qualidade das mudas produzidas ao longo de colheitas sucessivas. Objetivou-se com este trabalho avaliar a sobrevivência, o crescimento e a qualidade de mudas de cedro australiano, produzidas por miniestacas, obtidas de minicepas manejadas em sistemas de canaletões e em tubetes, ao longo das colheitas sucessivas. O experimento foi conduzido em casa de vegetação em delineamento inteiramente casualizado em esquema fatorial 2x4 (dois sistemas de minijardins e quatro colheitas de miniestacas). No sistema em canaletão foram realizadas seis colheitas de miniestacas aos 50, 86, 115, 149, 177 e 212 dias após recepagem e quatro no sistema em tubetes aos 115, 149, 177 e 212 dias após recepagem. Ao final de cada ciclo de produção (105 dias a partir de cada colheita), as mudas foram avaliadas quanto à sobrevivência, área foliar, massa seca da parte aérea, número e comprimento das raízes adventícias, massa seca do sistema radicular, as relações entre a altura e o diâmetro, massa seca da parte aérea e a massa seca das raízes e o Índice de Qualidade de Dickson. A sobrevivência das mudas não foi afetada pe...

Initial growth and photosynthetic characteristics of Hymenaea courbaril plants submitted to different concentrations of potassium

“…This index is considered an important indicator of plantlet quality, since the equilibrium of biomass distribution in the plant is taken into consideration. The results achieved were higher than the minimum 0.20 proposed by Silva et al (2016) [20], which indicate that the different concentrations of K + did not cause the decrease of quality for H. courbaril plants analysed in the experimental conditions. Psidium guajava seedlings showed similar results, so that the different K + doses did not affect growth characteristic, including DQI [21].…”

Análise da superfície usinada da madeira de clones de <i>Toona ciliata</i> M. Roemer var. <i>australis</i>

“…Entre as novas espécies que estão ganhando destaque no Brasil, podemos citar o cedro australiano (Toona ciliata M. Roemer var. australis), cuja madeira, segundo Silva et al (2016), se assemelha ao cedro brasileiro nativo (Cedrela spp. Vell.).…”