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 doublephase 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 mg l -1 IBA (indole-3-butyric acid), while 0.8 mg l -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 ).

In Vitro Propagation Of ‘Gisela 5’ Rootstock As Affected By Mineral Composition Of Media And Plant Growth Regulators

“…The number of roots per explant and root length were highest in the medium supplemented with 2 mg•l -1 IBA (Table 8). Similar results were reported by Dorić et al (2014) who obtained the maximum number of roots and roots length in 'SV1' selection (P. fruticosa) at the highest IBA concentration.…”

“…DKW medium containing 0.5 mg•l -1 BA was used for Gisela slow growth storage (Lambardi et al 2006). Dorić et al (2014) used this medium to the in vitro propagation of different cherry rootstocks, including 'Gisela 6'. Although MS medium is still most widely used, it is often replaced by media of lower salt concentration, especially those with lower nitrogen content, including the content of ammonium nitrate which is 1650 mg•l -1 in MS medium and 1416 and 400 mg•l -1 in DKW and WPM, respectively.…”

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).…”