Effects of different doses of IBA on ex vitro rooting of microcuttings in the floating perlite bed and growth performance of micro-propagated plants in pyrodwarf pear rootstock

In this study, the effects of control and IBA doses of 25, 50, 100 and 150 mg/L on ex vitro rooting of micro cuttings of Pyrodwarf pear rootstock (Pyrus communis) in floating perlite bed, and some treatments that were effective in ex vitro rooting on plant growth performance were investigated. In the first experiment, micro cuttings were dipped for 10 seconds in IBA solutions except control before planting in floating perlite bed. The cultures were kept for 4 weeks in a climate chamber at 25±2ºC with a photoperiod of 16 hours light (35 μmol∙m-2∙s-1) and 8 hours darkness. In the second experiment, plantlets rooted in the floating perlite bed with control, 25 and 50 mg/L IBA were planted in a mixture of peat and perlite, and developed under greenhouse conditions from June to November. In the first trial, there was no statistically significant difference between treatments in rooting percentages (77.8±2.2%-81.1±4.0%), number of roots (1.9±0.2-2.5±0.2 roots/micro cuttings) and length of the longest root (22.8±0.2-36.8±0.2 mm). The effects of the treatments on plant height, number of leaves and internodes were generally similar during the vegetation period. At the end of the vegetation period, there was no significant difference between the treatments in plant height (111.7±6.6-118.7±4.1 mm). However, the highest values were found in 50 mg/L IBA treatment with a significant difference in other traits. Stem diameter was 4.5±0.1 mm, fresh and dry root weights were 1173.0±126.0 and 196.5±12.8 mg/plant, and fresh and dry shoot weights were 1547.8±30.6 and 704.7±16.7 mg/plant, respectively. In conclusion, the floating perlite bed technique is effective in ex vitro rooting and simultaneous acclimatization of micro cuttings of Pyrodwarf rootstock, and dipping of micro cuttings in 50 mg/L IBA solution for 10 seconds before planting improves the growth performance of micropropagated plants at later stages.