EFFECT OF VARIOUS CULTURE CONDITIONS ON PROLIFERATION AND SHOOT TIP NECROSIS IN THE PEAR CULTIVARS ‘WILLIAM’S’ AND ‘HIGHLAND’ GROWN IN VITRO

The effect of culture media (Murashige & Skoog, MS; ½ MS; woody plant medium, WPM; and Quoirin & Lepoivre, QL salts with MS vitamins), pH (5.2–7), Ca and benzyladenine (BA, 0–10 μM) concentration, and combination of BA with gibberellic acid (GA₃) on shoot proliferation and shoot tip necrosis was studied in shoot cultures of pear cvs ‘William’s’ and ‘Highland’. Shoot proliferation rate, quality of shoots (length, fresh weight) as well as shoot tip necrosis were dependent on cultivar, culture medium and BA concentration.
QL medium resulted in a significantly higher shoot proliferation rate of ‘Highland’ (21 shoots/explant). Alternatively, in ‘William’s’ MS resulted in best shoot quality but in a lower number of shoots/explant (4.1). BA at 2.5 μM or higher concentration improved shoot proliferation rate in both cultivars. ‘Highland’ proved to be more susceptible to shoot tip necrosis (max. 64% in QL) compared to ‘William’s’ (max. 31% in ½ MS). However, WPM used for ‘Highland’ cultures resulted in a very low percentage of shoot tip necrosis (10%), similar to the percentage observed in ‘William’s’ (14%). pH and BA concentration with or without GA₃ had no effect, while high Ca concentration in ½ MS increased shoot tip necrosis.
Duration of in vitro culture significantly affected shoot tip necrosis development in both cultivars.

XXV International Horticultural Congress, Part 10: Application of Biotechnology and Molecular Biology and Breeding – In Vitro Culture.

K. Grigoriadou, N. Leventakis, M. Vasilakakis

in vitro culture, pear, shoot tip necrosis

https://doi.org/10.17660/ActaHortic.2000.520.10