Breeding and Biotechnology of Plant and Flower
M. E. Naddaf; E. Ganji Moghadam; Gh. Rabiei; A. Mohammadkhani
Abstract
Introduction Sweet Cherry (Prunus avium) belongs to the Rosaceae family, which due to vegetative propagation problems, in vitro propagation is recommended to increase mass and disease-free production. Micropropagation has many advantages over other vegetative methods. Although the most suitable ...
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Introduction Sweet Cherry (Prunus avium) belongs to the Rosaceae family, which due to vegetative propagation problems, in vitro propagation is recommended to increase mass and disease-free production. Micropropagation has many advantages over other vegetative methods. Although the most suitable organ that preserves the genetic characteristics of the cultivar is bud meristem, plant regeneration from meristem culture is difficult in many species of woody plants, so micro-grafting is a suitable technique to overcome these problems. The aim of this study was to investigate the effect of scion size and origin of commercial sweet cherry cultivars interact with micrografting on the vegetative rootstocks.Materials and Methods In this study, factorial experiment was used as a test unit in a completely randomized design (CRD) with two factors in five replications and ten seedlings per replication. The first factor was cultivar in seven levels (B: Bing, D: Dovomres, H: Haj Yousefi, P: Pishres, S: Siah- Mashhad, T: Takdaneh, Z: Zard) and the second factor was scion type in four levels (M1R1: 2 mm in vivo explant, M2R1: 5 mm in vivo explant , M1R2: 2 mm in vitro explant and M2R2: 5 mm in vitro explant). To prepare the scion, 1.5 to 2 cm long explants were isolated from shoot tips and then disinfected with 75% ethanol and 20% Sodium hypochlorite. After rinsing with distilled water, the shoot tips with 2 and 5 mm length were extracted for in vivo explants. In vitro explants were obtained from shoo tips that was previously established in MS culture medium with supplement of 1 mg.l-1 of BAP. The meristems were prepared in 2 and 5 mm and used as in vitro explant. 5 cm length in vitro shoots of sweet cherry ‘Gisella 6’ was used as rootstock. Micro-grafting was performed according to the standard method for sweet cherries. Micro-grafted plantlets were transferred to MS medium supplemented with 1 mg.l- l BAP, and kept under low light (100 lux) condition for one week, then transferred to growth chamber at 27.1 °C photoperiods 16/8 hrs light/darkness (1500 lux). In order to induce root, grafted plantlets were transferred to Perlite: MS medium supplement with 1 mg.l- l IBA. After rooting, plants were placed in polyethylene pots containing perlite: peatmoss (1:1) for acclimation. Micro-grafting success indices were recorded in each of the micro-grafted plantlets. The data were analyzed by SAS statistical software (9.1) and the means were compared by Duncan's multiple range test (1 and 5 % of probability levels).Results and Discussion The results showed that in all indices there was a significant difference between scion types and cultivar scion type interactions except grafting time, but there was no difference between cultivars (except longitudinal growth of scion). Among the scion types, the 5 mm in vitro scion (M2R2) had the highest micro-grafting success rate (42%), number of leaves (3.7), longitudinal growth (6.3 cm) and taken grafting time (two days). Finally, in successful micro-grafted plants, ‘Pishres’ cultivar had better results in rooting (32.8%) and ‘Zard’ cultivar in acclimation (3.4%) traits. Probably the presence of leaves led to better nutrient supply and surface contact, so it mostly improved the success of micrografting technique. In this study, micro-grafting success indices were lower than previous reports using seedling rootstocks. This might be due to difficult grafting operations, poor rootstock-scion communication, low physiological activity, and high in vitro oxidase activity. In the type of scion, micro-grafting success rate of 5 mm in vitro scions (include leaf primordia), was better than 2 mm scions (without leaf primordia). These results were consistent with most reports in sweet cherries and other stone fruit that were more successful in micro-grafting using larger in vitro explant.Conclusion Based on our results, it can be concluded that the micro-grafting method in sweet cherry micro-propagation is a fast practical method with high potential for production and regeneration of healthy orchards, which is also possible for other cultivars. In micro-grafting success, in vitro explants are preferable to explants taken directly from in vivo mother trees, and the use of larger explants for scion is recommended due to the presence of leaf primordia in micro-grafting success. However, smaller-size explants are more likely to produce healthy plants.
Ahmad Sharifi; Seyyedeh Mahdiyeh Kharrazi; Fatemeh Keykha Akhar; Abdolreza Bagheri; Elahe Samari; Maryam Moradiyan
Abstract
Introduction: Gerbera is one of the most important ornamental plants in the world. The importance of Gerbera is due to its beauty, diversity and economically aspects. Traditional propagation methods such as crown division and cutting methods are not suitable for obtaining disease free plants and rapid ...
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Introduction: Gerbera is one of the most important ornamental plants in the world. The importance of Gerbera is due to its beauty, diversity and economically aspects. Traditional propagation methods such as crown division and cutting methods are not suitable for obtaining disease free plants and rapid multiplication. These methods also do not have the capacity to fulfill global demands. Therefore, obtaining efficient protocol for micropropagation of this ornamental plant is necessary.
Materials and Methods: In this study the effect of various factors on in vitro regeneration, proliferation, rooting and acclimation of gerbera capitulum explants were analyzed in four separate experiments. Capitulum explants were first washed with running tap water for 30 min then surface sterilized by dipping in 1.5% sodium hypochlorite solution for 15 min and rinsed with sterile distilled water, followed by immersing in 0.1 % mercuric chloride solution for 10 min. To remove mercuric chloride residue, capitulum was rinsed with sterile distilled water. Subsequent washing was done with sterile distilled water for three times. Sterilization steps were done under laminar air flow hood. For regeneration, eight genotypes of gerbera capitulum explants (Famous, Sunway, Red Pearl, Pink Snow, Popov, Balance, Dune, Eagle)were cultured on solid MS medium containing several cytokynins, BA, TDZ, 2IP or KIN (4 mg/l) in combination with IAA (0.2 mg/l). In proliferation stage, the effect of different concentrations of BA was evaluated on proliferation rate of Sunway regenerated explants. In the rooting stage, Sunway genotype plantlets were cultured on ½ MS medium containing NAA, IBA or IAA (1 mg/l) or ½ MS medium without any hormones. The pH of the medium was adjusted to 5.7-5.8 prior to autoclaving (15 min at 121 oC and 1.5 kg.cm-2 pressure). The cultures were incubated in a growth chamber at 25±2 oC with a 16-h photoperiod (2500-3000 Lux) provided by cool-white fluorescent lamps. For acclimation of rooted plantlets, different substrates used as follow: 1- perlite, 2- perlite: Cocopeat, 3- Cocopeat: peat moss, 4- Cocopeat: peat moss; treated with fungicide.
After 30 days, the response of explants was evaluated for each experiment. Data preparation was done in the Excel program and data analysis was done using JMP-8 software. Mean comparison of the treatments was done by Tukey test and finally the charts were drawn using the Excel program.
Results and Discussion:The results of regeneration stage showed that application of MS media containing kinetin or 2IP did not make an appropriate response to capitulum explants and no regeneration was observed in this condition. The medium containing 4 mg/l BA and 0.2 mg/l IAA indicated the highest percentage of regeneration in all genotypes.
The highest regeneration was observed in Sunway genotype with an average of 21.96%. On the other hand no regeneration was observed in Eagle genotype. In terms of the number of regenerated plantlet, the highest number (61.2) was attributed to the Sunway genotype while no plantlet was recorded for Eagle genotype. No significant differences were also observed between Pink Snow and Dune genotypes.
For the proliferation stage, only Sunway genotype was utilized due to its vigorous growth in comparison to other genotypes. In this stage, the highest (6 regenerated plantlets) and the lowest (1 regenerated plantlet) regeneration rate were observed in MS medium containing 2 mg/l BA and hormone-free medium, respectively. Hormone-free ½ MS medium and ½ MS medium containing 1 mg/l IAA or IBA, indicated the highest rooting rate (100% rooting) while medium containing 1 mg/l NAA showed 55% rooting rate. It seems that the application of NAA in the medium composition had the lowestimpact on the rooting of regenerated plantlets. At the end of the experiment, the highest (90.42%) and the lowest (47.5%) acclimation rate was obtained in peat moss + cocopeat + fungicide medium and perlite medium, respectively.
Conclusions: Generally, for shoot induction of gerbera through capitulum culture, application of MS medium containing 4 mg/l BA and 0.2 mg/l IAA is recommended. It is also concluded that for proliferation stage, the MS medium containing 2 mg/l BA showed the highest rate of regeneration. Using of Hormone-free ½ MS medium is economically affordable. Finally for acclimation of the plantlets, application of peat moss + cocopeat + fungicide medium is recommended.
