Micropropagation of Greenberry (Rubus erythroclados)

Rubus erythroclados is a Brazilian native species with green, sweet fruits that have great potential for fresh market sales and for processing. However, this species is difficult to propagate, and there are no studies about its micropropagation. This study aimed to evaluate the multiplication and rooting of greenberry shoots treated with different concentrations of benzyladenine and indolebutyric acid. Nodal segments with a length of 0.5 cm and one bud were used as explants. After establishment in cultured medium MS, different BA concentrations were tested (1, 5 and 10 µM). In the multiplication stage, the experimental design was completely randomized, with four replications of twelve test tubes per plot. Two subcultures were performed every 60 days. The variables evaluated were the number of shoots per explant, the length of the largest shoot, the number of leaves per shoot, the percentage of dead explants, and the percentage of hyperhydration shoots. The averages of the variables were submitted to an analysis of variance and Tukey’s test at 5% probability using the statistical program Sisvar®. The rooting experiment utilized a completely randomized design, with four replications of twenty shoots per plot. The following concentrations of IBA were tested: 0, 3, 6 and 9 μM. After 60 days of culture, the percentage of rooted, dead and live microcuttings; the number of roots per microcutting; the root length; the height of the plants; and the number of leaves per plant were observed. The average values were submitted to regression analysis using the statistical program Assistat®. The highest multiplication rate (>10) was observed in the culture medium supplemented with 10 μM BA. However, the percentage of hyperhydration shoots was very high at this concentration. The treatment without a growth regulator resulted in only one shoot per explant. The maximum rooting of the microcuttings (48%), as estimated by the regression equation, was obtained with 5 μM IBA, and the highest number of roots was obtained with 5.8 μM IBA.