61 AJCS 5(1):61-65 (2011) ISSN:1835-2707 Micrografting of almond (Amygdalus communis) cultivar ‘Nonpareil’ Çiğdem Işıkalan 1 *, Süreyya Namli 1 , Filiz Akbas 2 , Bekir Erol Ak 3 1 Dicle University, Faculty of Science, Department of Biology, 21280, Diyarbakır-Turkey 2 Batman University, Faculty of Science and Arts, Department of Biology, Batman-Turkey 3 Harran University, Faculty of Agriculture, Department of Horticulture, Urfa-Turkey *corresponding author: ahrar@dicle.edu.tr Abstract Effects of plant growth regulators (PGRs) were investigated on micropropagation of scions and micrografting of almond (Amygdalus communis) cultivar ‘Nonpareil’. In vitro germinated wild almond seedlings developed from seeds were used as rootstocks. The mature apical or subapical shoot tips of almond cultivar ‘Nonpareil’were used as material for establishment of the microscions cultures. The shoot tips were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations (0.0, 0.5, 1.0, 1.5, 2.0, 4.0 mg l -1 ) of N 6 -benzylaminopurine (BAP). The data showed that the increase in BAP concentration resulted in significant reduction at the shoot regeneration rate. Among all tested groups, the highest regeneration rate was obtained on medium containing 1.0 mg l -1 BAP. The regenerated adventitious shoots from in vitro cultures were cultured on media containing BAP (0.5, 1.0, 1.5 mg l -1 ) combined with 0.2 and 0.4 mg l -1 indole butyric acid (IBA) separately for development of shoots. The best respond was observed from MS medium supplemented with 1.0 mg l -1 BAP + 0.2 mg l -1 IBA. The effects of BAP and IBA (1.0 mg l –1 ) were studied on development of micrografted plantlets. Regenerated shoots tips, which were micrografted onto in vitro germinated wild almond seedlings. The results indicated that the most graft rate and new shoots formation were obtained 1.0 mg l –1 BAP. In vitro micrografted plantlets were successfully transferred into commercial plastic pots for acclimatization. Keywords: Almond, Nonpareil, Micrografting, Rootstocks, Microscions. Abbreviations: PGRs; Plant growth regulators , BAP; N 6 -benzylaminopurine , IBA; Indole-3-butyric acid, MS; Murashige and Skoog (1962) medium Introduction Modern biotechnology techniques can hasten the production of new genotypes and broaden the gene pool avaible for improvment of woody fruit species (Ainsley et al., 2001). However, fruit trees are amongst the most recalcitrant for in vitro culture, and regeneration of adventitious shoots from adult explants has proven difficult (Miguel et al., 1996). Conventinal breeding of woody fruit species is a slow and difficult process due to high levels of heterozygosity and long generation cycles ( Sriskandarajah et al., 1994). To minimize the problem of enormous genetic variation and to obtain genetically identical populations, vegetative propagation via layering or cutting is applied. However, these techniques are inefficient due to the large number of problems faced in this fruit species in in vivo rooting of cutting. Because of the difficulties encountered with rooting of cuttings of almond cultivars, grafting and budding onto seedling rootstocks is the usual method used for vegetative propagation (Yıldırım et al., 2010). Microshoots that are difficult to root, or do not form roots at all in vitro, can be micrografted onto rootstocks to obtain rooted plantlets (Thimmappaiah Putra and Anil 2002). In vitro micrografting has been reported in many plants such as cashew (Ramanayake and Kovoor 1999; Mneney and Mantell 2001; Thimmappaiah Puthra and Anil 2002), pistachio (Abousalim and Mantel 1992; Onay et al., 2002; Onay et al., 2007), olea europaea (Revilla et al., 1996), almond (Channuntapipat et al., 2003), Prunus avium L.(cherry) var. (Amiri 2006). Micrografts, developed in the 1970s, involve the grafting of millimeter-size vegetative meristems. Micrografting is mostly used for obtaining virus-free plants, separating viruses in infections, breeding specific genotypic combinations, and for studying graft incompatibility between scions and rootstocks (Burger 1985; Navarro 1988). In vitro micrografting may provide several advantages such as elimination of viruses, rejuvenation of mature tissues, year round plant production, enhance compatibility studies and correlative relation between rootstocks and scions, breeding for specific genotypic combinations to increase plant productivity, and extention of ecological limits of a particular plant species (Richardson et al., 1996; Hartmann et al., 1997). Compared to traditional grafting with in vitro grafting procedure, micrografting has several potential advantages over the traditional procedure; it is much more rapid, requires much less space, particularly disease-free planting materials and producing genetically uniform plantles. In in vitro micrografting studies, ensuring good contact between the microscion and the rootstock was essential for the graft unions to form successfully. Also, the optimization of culture conditions and media is significant for micrografting studies. The objective of the present study was to investigate influence of BAP for establishment of the microscions cultures and micrografting procedure was to develop for almond cultivar ‘Nonpareil’.