Factors Affecting Shoot and Root Initiation from Cultured Rose Shoot Tips1

Abstract

In vitro -derived shoot tips of ‘Improved Blaze’ rose ( Rosa hybrida L.) proliferated on a medium containing MS salts, thiamine·HCl (0.5 mg/liter), pyridoxine·HCl (0.5 mg/liter), nicotinic acid (0.5 mg/liter), glycine (2.0 mg/liter), i -inositol (100 mg/liter), sucrose (30 g/liter), Bacto agar (8 g/liter), indoleacetic acid (IAA) (0.3 mg/liter) and 6-benzylamino purine (BA) (1.0, 3.0, or 10.0 mg/liter). A 6-fold multiplication could be obtained after 4 weeks; no further increase in multiplication was obtained by extending the length of the culture period. In vitro -proliferated shoots cultured for 10 to 14 days on the basal medium without growth regulators initiated roots and could be successfully transplanted into soil; however, both root formation and transplantability were enhanced by α-naphthaleneacetic acid (NAA) (0.03 or 0.10 mg/liter) or IAA (1.0 mg/liter) and by lowering the MS salt concentration to ¼ or ½ strength. Although the degree of root initiation and successful establishment in soil was variable, 90 to 100% successful transfer to soil could be obtained.