Effects of Nutrient Salt Formulations and 6-Benzylaminopurine on Micropropagation of Blue Moon Wisteria

Wisteria frutescens var. macrostachya ‘Blue Moon’, a Kentucky Wisteria, is a flowering vine native to the United States. W. frutescens var. macrostachya is probably the hardiest of the wisteria and ‘Blue Moon’ is one of the two hardiest cultivars in Zone 4 to 8(9). ‘Blue Moon’ is great addition to a landscape as a fast growing vine, which has long purple racemes during the spring. Although it is hardy, ‘Blue Moon’ does not have the profuse blooming that many species of wisteria have. Also, wisteria grows very quickly making sometime invasive and looking unkept. When grown from seed it might not bloom for 10 years, making breeding a challenging, long-term commitment. Because of its hardiness it is of interest to improve this species in terms of flowering and dwarfing or slowing growth. Currently there is no published micropropagation protocol for Wisteria. The objective of this study was to establish a micropropagation protocol for ‘Blue Moon.’ A 4 x 5 factorial of four nutrient salt formulations (MS, WPM, DKW, and LP) and six concentrations of 6-benzylaminopurine (BA) (0, 2, 4, 8, 16 μM) were used to determine shoot growth and shoot proliferation of viable microshoots. Bud explants were 5mm in length and initiated into cultures on the various factorial media plus 30g/l sucrose and 7g/l agar at a pH of 5.8. Explants were incubated approximately 30 cm beneath cool white fluorescent lamps that provide a photon flux of approximately 30 mmol m^-2s^-1 for a 16-h photoperiod at 25±3°C. Nodal explants were transferred every 6 weeks for a total culture period of 12 weeks. At each transfer date, data was taken on shoot number and propagation number, which entailed a bud on at least 5mm length of shoot. Based on number of shoots produced per nodal segment, DKW and WPM salt formulations and higher concentrations of BA (4, 8 and 16 μM) produced a greater number of shoots. With respect to propagation number, there was a significant interaction between nutrient salt formulation and BA concentration with DKW and 4 μM BA producing the most propagules per nodal segment as compared to other combinations evaluated. To date, this is the first report of successful micropropagation of W. frutescens var. macrostachya.