In vitro propagation protocol for new stone fruit rootstocks

The clonal rootstocks are important for increasing orchard density, uniformity of trees and high yields. Micropropagation has played an important role in the production of disease-free plants and in the rapid multiplication of rootstocks with desirable traits. Successful micropropagation of many rootstocks is influenced by several factors including in vitro conditions. Experiments were performed at the plant tissue culture laboratory of the Research Institute for Fruit Growing (RIFG) PitestiRomania, to optimize tissue culture protocol for explants growth of four perspective stone fruit rootstock selections: `RoP8803001, `RoP8802011, 'B 83/8, and `Mirodad 3'. For establishment stage three growth regulators combinations (mg L-1): V1 (BAP 0 IBA 0), V2 (BAP 0.5-IBA 0.01), V3 (BAP 1.0-IBA 0.1) were used. Two basic media (BM) were used: BM 1 (Murashige and Skoog- MS, 1962) and BM2 (Quoirin and Lepoivre QL, 1977 with Linsmaier and Skoog- LS vitamins, 1965). The experimental results regarding explants growth reveals that whatever the composition of the basic medium, the best hormonal combination was composed of BAP 1.0 mg L-1 and IBA 0.1 mg L-1. The percentages of explants growth for this combination were very little different, depending on the two basic media. However, higher values were obtained in the presence of BM 2. The percentages obtained for all four rootstock selections were between 16.6 (`Mirodad 3') and 41.6% (`83/8 B'). The results show that these rootstock selections can be propagated by tissue culture.