Rapid Propagation of Sweet and Sour Cherry Rootstocks

Abstract

The paper presents a protocol for micropropagation of Prunus sp. rootstocks included in the sweet and sour cherry breeding program. Germplasm diversity for rootstock breeding derives from natural populations, where conditions and biological vectors for systematic infection with viral diseases are constantly present. The establishment of aseptic culture depends primarily on the explant type, as all selections were collected from natural habitat. For nearly all investigated selections, dormant buds were the favored source, due to enabling rosette initiation in more than 58% cases. In P. cerasus L. selections, 100% contamination was noted when shoot tips were used as an explant source. Significant influence of the double-phase medium on the number and height of multiplied shoots was observed in the standard cherry rootstock, ‘Gisela 6’. For P. fruticosa Pall., selection ‘SV1’ and ‘SV2’, and P. cerasus ‘D6’ selection, the double-phase medium also had a significant effect on the height of multiplied shoots, when compared to solid DKW (Driver and Kuniyuki Walnut) medium. Genetic variability of selections within the investigated species resulted in variable plant rooting success. Adding Fe-EDDHA (Ethylenediamine di-2-hydroxy-phenyl acetate ferric) in the 200 mg l-1 concentration to the rooting medium significantly enhanced the percentage of rooted plants. The highest rooting percentage was noted for ‘Gisela 6’ and ‘D6’ genotype at 1 mgl-1 IBA (indole-3-butyric acid), while 0.8 mgl-1 was the optimum concentration for P. mahaleb L. ‘M1’ selection. P. fruticosa genotypes required significantly higher IBA concentration for rooting (2.5 and 3.5 mg l-1).

Use of in vitro propagation of ‘Oblačinska’ sour cherry in rootstock breeding

“…Gisela 5 low-vigorous cherry rootstock is mainly propagated by micropropagation throughout the year (Ružić and Cerović, 2002;Ružić and Cerović, 2003). Bošnjaković et al (2013) and Dorić et al (2014) reported successful micropropagation when dormant buds, rather than actively growing shoot tips, were used as an explant source in P. fruticosa Pall. and P. mahaleb L., regardless of genotype diversity.…”

“…To break dormancy, Druart (2013) recommended cold storage of twigs for 1 month at 2 °C. In P. fruticosa and P. mahaleb, dormancy did not adversely affect culture initiation, multiplication, shoot elongation, or rooting (Bošnjaković et al, 2013;Dorić et al, 2014).…”

“…Germplasm diversity for rootstock breeding derives from natural populations where infections and viral diseases are constantly present (Dorić et al, 2014). A very important advantage of introducing in vitro germplasm into rootstock breeding is the potential for the recovery of virus-free plants from infected germplasm through shoot meristem culture (Druart, 2013).…”

Micropropagation of rootstocks of stone fruit cultures in vitro

“…The ability of explants to regenerate depends on the initiation period. As a rule, explants selected during the period of active growth of shoots have the highest regenerative activity [10].…”

“…One of the factors for the success of reproduction is the composition of the nutrient medium. Most often, for clonal micropropagation of rootstocks of small-seed cultures (cherries, sweet cherries), modified media of Murashige and Skoog (MS), DKW, WPM, Schenk and Hildebrandt (SH) are used, with various variations of hormonal substances, vitamins, macronutrients, sucrose [10][11][12][13][14][15] , for large-seed crops (plum, cherry-plum, apricot, peach) -the environment of Murashige and Skoog (MS), DKW, Quorina-Lepuavra (QL) [4,[16][17][18][19]. Optimizing the composition of the environment for a specific plant genotype is of particular importance, because even within the same species, plants may exhibit different reactions.…”