Acclimatization of micropropagated apple rootstock Seleção 69 in different substrates

The stage of acclimatization is a limiting factor for most micropropagated plants due to losses of inoperative stomata and inactivity of photosynthesis. One of the most important factors during acclimatization is the ideal choice of substrate. Therefore, the objective of this study was to determine the best substrates for acclimatization of the micropropagated apple rootstock Seleção 69. To evaluate the best substrate, a completely randomized design with seven replications was used. The explants of micropropagated apple rootstock S69 were transferred to trays with 128 cells. These explants were planted on substrates with different mixtures of Plantmax, rice hulls and sand. Spray irrigation was performed daily. After 30 days the evaluation of the root and shoot dry matter was realized. The results were analyzed by variance and Scott-Knott’s test of means. Results showed that the best substrate for acclimatization were T1, T2 and T3, which presented shoot dry matter of 4.80, 4.14 and 5.03mg per plant, respectively. For roots the best dry
matter production was obtained by substrates T1, T2, T5 and T6, with 0.96, 0.95, 1.23 and 1.39mg per plant, respectively. Considering both the shoot and the root dry matter, it can be concluded that the best substrates were T1, T2 and T6. However, substrates T1 and T6 must be selected for presenting the best physical and chemical characteristics.