Callus formation from Malus x domestica cv. 'Jonathan' protoplasts

Plant regeneration from mesophyll protoplasts of Williams' Bon Chretien (syn. Bartlett) pear (Pyrus communis L.)

Leaf protoplasts of axenic shoot cultures of Pyrus communis L. cv. Williams' Bon Chretien (syn. Bartlett) underwent cell wall regeneration and division to give multicellular colonies in a modified Murashige and Skoog medium which lacked ammonium ions, but supplemented with 1-naphthaleneacetic acid (NAA), 4-indole-3yl-acetic acid, 6-benzylaminopurine (BAP) and casein hydrolysate. Protoplast-derived colonies gave callus on Murashige and Skoog salts medium with NAA and BAP and exhibited shoot regeneration on half-strength Murashige and Skoog medium supplemented with 0.2 mg 1(-1) 4-indole-3yl-butyric acid, 2.0 mg 1(-1) BAP, 0.2 mg 1(-1) gibberellic acid, 50 mg 1(-1) casein hydrolysate and 10 mg 1(-1) Ca-pantothenate. Following rooting, protoplast-derived plants of pear were transferred to the glasshouse where they completed acclimatization.

Callus formation from leaf mesophyll protoplasts of Malus Xdomestica Borkh. cv. Greensleeves

Large yields (1.85 × 10(7)/g.f.wt.) of viable protoplasts were obtained from leaves of axenic shoot cultures of Malus Xdomestica Borkh. cv. 'Greensleeves'. Protoplasts cultured in liquid or agarose semi-solidified KM8P medium underwent cell wall regeneration and colony formation.Protoplast-derived cell colonies developed to callus on semi-solid KM8 medium. This is the first report of callus formation from mesophyll protoplasts of apple.