Increased CaCl2, MgSO4, and KH2PO4 improve the growth of micropropagated red raspberries
Abstract
The genetic variation present in red raspberries makes it difficult to successfully apply a standard in vitro growth medium. An initial study modeling Murashige and Skoog (MS) medium minerals concluded that the mesos (CaCl2, MgSO4, and KH2PO4) components significantly affected red raspberry (Rubus idaeus L.) shoot quality and growth. To determine the effects of the individual mesos components, a three-dimensional design based on response surface methodology was employed. Shoot cultures of five cultivars were evaluated for quality, multiplication, shoot length, leaf characteristics, and mineral content. The resulting model indicated that improved growth and quality of all cultivars required significantly higher (p ≤ 0.05) concentrations of some or all of the three mesos compared to MS medium. Higher concentrations of CaCl2 and KH2PO4 significantly increased shoot length for most cultivars. MgSO4 had the greatest effect on leaf characteristics. Shoot mineral content was directly related to the mineral content of the medium. Although individual cultivars varied in optimal amounts of each component, high-quality shoots could be produced for all cultivars with 2.5–3.0× the MS concentrations of all three salts.
Keywords
Calcium Growth medium Magnesium Phosphorus Rubus