Micropropagation and in Vitro Grafting Techniques to Assist the Selection of a Pistachio Rootstock From a Population of Terebinth (Pistacia Terebinthus L.) Collected in the Se of Spain

Abstract

Pistachio culture is hampered both by the difficulty of propagation by grafting varieties of interest and by the lack of a clonal selected rootstock. The application of in vitro culture techniques would allow the clonal propagation of Pistacia species, as well as to perform in-depth studies of factors affecting grafting. In vitro P. vera cultures were initiated from nodal explants, whereas cultures of P. terebinthus were initiated from in vitro-germinated seeds. The multiplication rate of both species in vitro was close to 2 shoots per shoot every 3 weeks. A high rooting percentage (82%) of P. terebinthus was obtained in a modified WPM medium and plants were successfully transplanted to the greenhouse. Shoot apices of P. vera of 10-20 mm length were grafted in vitro on rooted or unrooted shoots of P. terebinthus in which the apex was removed, and the evolution of the graft unions was studied. Over 70% of the grafted plants survived during the first 3-5 weeks and some plants continued their growth in the greenhouse. Similarly, control selfgrafted P. terebinthus were studied, and these homografts showed that while the technique of grafting in vitro is promising in studying graft evolution, it needs to be improved by identifying the factors that affect cell necrosis.

A novel approach for propagation of recalcitrant pistachio cultivars that sidesteps rooting by ex vitro grafting of tissue cultured shoot tips

“…Seedlings of terebinth (P. terebinthus L.) were obtained from wild mature seeds. Seeds were peeled, washed in distilled water, dried, and cold stored at 4-5°C for at least 5 months (García et al 2011a). Seeds were then sowed in forest cells containing Pindstrup substrate, a proprietary mixture of peat:perlite (Pindstrup Mosebrug S.A.E.…”

Micrografting of Pistacia vera L.: A review

“…Despite the production of rootstocks from seeds for micrografting in vitro or in vivo, P. terebinthus rootstocks were micro-propagated in vitro, and the produced micro-cuttings with and without roots were micro-grafted in vitro with in vitro scions of P. vera. Some of the successful grafted plants could be acclimatized in vivo (Lorente et al, 2011).…”

“…The results showed that P. vera gave rise to the best stem diameter in comparison to P. terebinthus and P. khinjuk, which is crucial for holding the micro-scions. In the continuation of the P. vera micrografting, Lorente et al (2011) obtained P. terebinthus rootstocks in vitro as micro-cuttings, and rooted and unrooted ones were micro-grafted with in vitro scions of P. vera. Following 3-5 weeks, 44% of the grafted plants survived and growth continuing was noted in some of them in the greenhouse.…”

“…Given that environmental conditions are out of our control, all of these contribute to graft success rates that are typically poor. In contrast to other fruit plants where graft compatibility is the main concern, pistachio grafting appears to be impacted by the scion's and rootstock's physiological conditions (Lorente et al, 2011). Thus, a better grafting method that contributes to elevated success percentage is inevitable.…”