INFLU\ucaNCIA DA POSI\uc7\uc3O DAS MINIESTACAS NA QUALIDADE DE MUDAS DE CEDRO AUSTRALIANO E NO SEU DESEMPENHO INICIAL NO P 3S-PLANTIO

Abstract

The Toona ciliata (Australian cedar), originated from Australia showed high acclimatization in Brazil, where it found appropriate conditions for its growth, particularly in southern Bahia and throughout the southeastern region. However, the plantings presented irregular stems. Besides the seeds are a limiting resource, in result of their production seasonality and short viability period. This study aimed the evaluation of the quality of cuttings grown from 6 cm length apical, middle and basal mini-cutting positions of the sprouts of the mini-strains - from seminal origin - and the initial growth of cuttings. It was established a multi-clone mini-garden containing a total of 284 mini-strains. After cutting off the sprouts of the seedlings - to originate the mini-strains - the mini-cuttings from the above different positions were collected. At the lifting time of the rooting sector, dry mass weight of shoot and root, length, diameter, number of adventitious roots and survival data were collected. The height and diameter were monitored fortnightly, starting from 80 days after the staking of the mini-cuttings. At the end of the production cycle, the dry mass weight of shoot, the root number, the diameter and the length of root cuttings were evaluated. Thirty percent of the cuttings were transplanted to pots of 3.8 L, in the open air where the height and basal diameter, the dry mass of shoot, the leaves and the roots were measured 60 days after the transplanting. Cuttings originated from the basal mini-cuttings at the end of the lifting time of the rooting sector, showed the highest height and diameter, however no difference was pointed out regarding to the basal diameter of cuttings originated from the middle position. There were no differences related to the shoot dry mass and the adventitious root number, the dry mass weight, the total length and the diameter of the adventitious roots of cuttings in relation to the mini-cutting positions in the sprouts. The survival was high, averaging 94.7 % for the apical, 96.3 % for the middle and 96.6 for basal position. Sixty days after transplanting, despite the differences in the diameter and the height of the cuttings at the end of the nursery phase, no difference in the height, the diameter and the dry mass weight of shoots, the leaves and the roots as pointed out in the treatments.O cedro australiano, origin\ue1rio da Austr\ue1lia, adaptou-se muito bem no Brasil, que apresenta condi\ue7\uf5es adequadas para o seu desenvolvimento, sobretudo no sul da Bahia e em toda a regi\ue3o sudeste. Por\ue9m, os plantios s\ue3o irregulares e as sementes s\ue3o insumo limitante, por sua sazonalidade de oferta e curta viabilidade. A finalidade deste estudo foi avaliar a qualidade das mudas obtidas de miniestacas apicais, intermedi\ue1rias e basais com 6 cm de comprimento oriundas de brotos de minicepas de Toona ciliata cultivadas em minijardim multiclonal em canalet\uf5es e o crescimento inicial das mudas no p\uf3s-plantio. Foi implantado um minijardim multiclonal em canalet\uf5es, contendo um total de 284 minicepas. A partir da parte a\ue9rea das mudas recepadas para forma\ue7\ue3o das minicepas, foram produzidas miniestacas de diferentes posi\ue7\uf5es. Na expedi\ue7\ue3o do setor de enraizamento foram coletados dados de massa seca da parte a\ue9rea e do sistema radicular, comprimento, di\ue2metro, n\ufamero de ra\uedzes advent\uedcias e sobreviv\ueancia. A altura e di\ue2metro das mudas foram monitorados quinzenalmente, a partir de 80 dias, ap\uf3s o estaqueamento. Ao final do ciclo de produ\ue7\ue3o, as mudas foram avaliadas com rela\ue7\ue3o \ue0 massa seca da parte a\ue9rea e do sistema radicular, n\ufamero, di\ue2metro e comprimento das ra\uedzes. Para avaliar as mudas ap\uf3s o plantio, 30 % das mudas foram transferidas para vasos de 3,8 L, onde foram avaliadas em altura e di\ue2metro do colo e, aos 60 dias, em massa seca do caule, folhas e ra\uedzes. As mudas provenientes das miniestacas basais, na expedi\ue7\ue3o da fase de enraizamento, apresentaram os maiores valores de altura e di\ue2metro, n\ue3o se diferenciando das intermedi\ue1rias com rela\ue7\ue3o ao di\ue2metro do colo. N\ue3o houve diferen\ue7as com rela\ue7\ue3o \ue0 massa seca da parte a\ue9rea e n\ufamero, massa seca, comprimento total e di\ue2metro das ra\uedzes advent\uedcias das mudas em fun\ue7\ue3o do tipo de miniestacas. Ap\uf3s a transfer\ueancia das mudas para a casa de vegeta\ue7\ue3o, a sobreviv\ueancia foi alta, com m\ue9dia de 94,7 % para apicais, 96,3 % para intermedi\ue1rias e 96,6 % para basais. Aos 60 dias ap\uf3s o plantio, apesar das diferen\ue7as observadas no di\ue2metro e altura das mudas ao final da fase de viveiro, n\ue3o houve diferen\ue7a no crescimento em altura, di\ue2metro e massa seca do caule, folhas e sistema radicular, em fun\ue7\ue3o dos tratamentos