Optimization of Tissue Culture Conditions for Micropropagation in Semi-dwarf M7 Apple Rootstock

Plant tissue culture technology, often used for plants large-scale multiplication. This commercial technology is based on micropropagation. Micropropagation is regeneration of organs, plants, tissues, cells and proliferation of true to type selected genotype, using in vitro culture technique. The improved plants produced by tissue culture method are stronger than those obtained from seed. Therefore in vitro propagation of M7 apple rootstock, often produces strong plants with accelerated growth. This research was performed with the aim of optimizing the in vitro propagation conditions of M7 rootstock and the survey effect of basal medias, different plant growth regulators on proliferation and rooting. Current study was performed with the aim of optimizing the in vitro propagation conditions of M7 apple semi-dwarfing rootstocks in the three separate experiments. In the first experiment, the effect of five types of basal media culture including, MS, 1/5MS, 2MS, WPM and B5, on shoot number and shoot length were studied. In the second experiment, the effects of two type of plant growth regulators, BAP and TDZ in various concentrations (0, 2.2, 4.4 and 8.8 µM) on shoot number, shoot length, node number, internode number and internode length was studied. In the third experiment, the effect of two types of basal media (MS and ½MS) supplemented with two types of plant growth regulation IBA and NAA in different concentrations (0, 1.5, 3 and 4.5 mg/l) under three and four days darkness on root number and root length was studied. Hardening of rootstocks in large perlite, small perlite, perlite with peat moss and peat moss separately was surveyed. According to results, the highest proliferation (15.66 shoots per explant) was observed in B5 media. In second experiment, BAP was more effective than TDZ on proliferation rate, number of nodes,internodes and reduce internode length characteristics. The highest proliferation (16.55 shoots per explant) was observed in BAP (2.2 µM). In the third experiment, highest root number (with mean 11.10 root per explant) was observed in ½MS media supplemented with 3 mg/l NAA. The results of the effect of growing media on M7 apple rootstock hardening showed that growing media of peat moss have most favorable results copared to other treatments. B5 media containing 1 mg/l BAP was detected as favorable and optimum media for the proliferation of M7 apple. BAP was more effective than TDZ on regeneration traits. incubation for three days under darkness showed better results than four days. According to the results of the third experiment, the best dark period, culture media type, plant growth regulator type and concentration were obtained, in three days darkness, ½MS media, NAA (3 mg/l) respectively