The blackberry propagation can be done through root cuttings, woody or herbaceous stem cuttings, or through tissue culture techniques. However, little is known about the initial growth and development of micro propagated blackberry seedlings. The aim of this work was to evaluate the initial development of micro propagated blackberry plants, previously acclimatized, obtained from the laboratory of tissue culture of Embrapa Temperate Climate, Pelotas, Brazil. Three cultivars and two thornless advanced selections (Selection 6 and 12) were evaluated in a randomized block design with four replications and five plants per plot. After 52 days in a greenhouse (01/25/2007), the plants were removed from the plastic bags and had their roots washed and sectioned. The following variables were evaluated; number of leaves; shoot length (cm), measured from the top to the button of the largest branch of the colon; root length (cm) measured from the crown to the longest root apex; fresh and dry weight of shoot and root (g). Under the conditions of this experiment, the selection 6 and cultivar Guarani had, respectively, the highest average number of leaves on 01/25/07. The highest average length of the aerial part of the blackberry plants was observed in cultivar Tupy. There was no significant difference on the average length of roots fresh and dry weight of shoots and roots among cultivars and advanced selections of blackberry. Under the conditions of this trial, it can be concluded that cv. Tupy has a higher growth, expressed by cane length. As a result, it has lager vigor during this phase and can be recommended for new blackberries plantings as the cultivar with better chances of success, among all the tested ones, during the present trial.
Rubus sp.; substrate; initial development; vigor
