ABSTRACT Sequoia sempervirens is different from other species not only for its excellent vigor and longevity, but also for quality wood productivity. The objective of this work was to evaluate the rooting of Sequoia sempervirens mini-cuttings in different cultivation environments. In both experiments, rooting was evaluated in time to determine the root development in each environment. Mini-cuttings from clone A228 from clonal mini-garden were used. In the first experiment the material was placed to take root in three different environments: greenhouse (GH), shadehouse (SH) and mini-tunnel, with evaluation performed every 30 days (from 30 to 150 days). In the second experiment, we compared the development and rooting in mini-tunnel, greenhouse with intermittent mist (GWIM), with weekly evaluations (from 30 to 93 days). Both experiments were installed in a completely randomized design, with subsequent evaluation of the survival percentage, percentage of rooted cuttings and number of roots emitted by rooted cuttings. Humidity and temperature data were also collected in all environments observed. The mini-tunnel was the most efficient place for sequoia mini-cutting, presenting higher survival, rooting and number of roots when compared to the shadehouse and the greenhouse. In addition, it provided rooting similar to the greenhouse with intermittent mist (close to 90%). It is recommended to keep mini-cuttings in a mini-tunnel or greenhouse with intermittent mist for a period of 90 days for proper rooting to occur. Good temperature control was also observed in this structure, as well as excellent humidity control. The mini-tunnel can be used for sequoia propagation by mini-cuttings as it has shown good rooting results (> 80%).
SUMMARY: Sequoia sempervirens is a fast-growing, long-lived tree with pest-resistant wood. The objective of this study was to quantify the adventitious rooting ability of sequoia clones in two environments as well as determining rooting behavior during the evaluation period. Mini-cuttings of five clones grown in a clonal mini-garden were planted for rooting in two different environments: a mini-tunnel and an intermittently fogging greenhouse. Weekly assessments (from 30 to 93 days) of the variables were performed: survival, rooted mini-cuttings and number of roots emitted. Rooting speed varied in relation to the clones, occurring mainly between 50 and 60 days after planting, with the appearance of new roots between 70 and 80 days. The cultivation environment promoted distinct responses in the rooting process, being earlier in the greenhouse environment, although with a higher index in the mini-tunnel at the end of the evaluation. The process of differentiation of mini-cuttings occurs initially with the formation of calluses, around 15 days, followed by rooting (between 30 and 60 days) and the subsequent appearance of new roots. The rooting of sequoia mini-cuttings can be done in a mini-tunnel, with good indexes for all clones. It is recommended to keep mini-cuttings in this environment for 90 days for good root formation.
RESUMEN: Sequoia sempervirens es un árbol longevo de rápido crecimiento con madera resistente a plagas. El objetivo de este estudio fue cuantificar la capacidad de enraizamiento adventicio de clones de S. sempervirens en dos ambientes, así como determinar el comportamiento de enraizamiento durante el período de evaluación. Se plantaron miniestaquillas de cinco clones cultivados en minihuertos clonales para enraizar en dos ambientes diferentes: mini túnel e invernadero de nebulización intermitente. Se realizaron evaluaciones semanales (de 30 a 93 días) de las variables: supervivencia (%), mini estaquillas enraizadas (%) y raíces emitidas. La velocidad de enraizamiento varió en relación con los clones, ocurriendo principalmente entre 50 y 60 días después de plantados, con la aparición de nuevas raíces entre 70 y 80 días. El ambiente de cultivo promovió respuestas distintas en el proceso de enraizamiento, siendo más temprano en el invernadero de nebulización intermitente, pero con un índice más alto en el mini túnel al final de la evaluación. El proceso de diferenciación de mini estaquillas ocurrió inicialmente con la formación de callos, alrededor de 15 días, seguido de enraizamiento (entre 30 y 60 días) y la posterior aparición de nuevas raíces. El enraizamiento de las mini estaquillas se puede hacer en un mini túnel, con buenos índices para todos los clones, y se recomienda mantener las mini estaquillas en este ambiente durante 90 días para una buena formación de raíces.
ABSTRACT We analyzed the rooting of sequoia mini-cuttings from different clones in the four seasons of the year and the use of the logistic model to estimate the time of maximization of rooting in each factor of analysis. Mini-cuttings of five clones grown in clonal mini-garden were placed to root in mini-tunnel in four seasons of the year. Weekly evaluations were performed (from 30 to 93 days) of these variables: survival (%), rooted mini-cuttings (%) and a number of emitted roots. These data were used to adjust the original logistic function. The experiment was set in completely randomized design, in a factorial scheme of 5 (clones) x 4 (seasons), using five replicates of 50 mini-cuttings per experimental unit. During the winter the lowest rooting of mini-cuttings was achieved (85%), with rates higher than 90% in other seasons. In winter, slower rooting also occurred, around 60-70 days, while in other seasons it was between 50-60 days after mini-cutting planting. The rooting process is dependent on the clones. Our data showed that four clones presented rooting greater than 90% and one less than 70%. In general, mini-cuttings can be performed at any time of the year, recommending the period of 90 days in mini-tunnel.