Cultivars of flowering dogwood (Cornus florida L.) are commercially propagated by vegetative methods such as rooting cuttings or grafting. The results of these methods can be unpredictable. A reliable method of producing dogwoods through tissue culture would be very useful to rapidly produce many copies of important genotypes with horticulturally important characters such as resistance to diseases. One of the primary difficulties of propagating dogwoods (seedlings only) by axillary bud multiplication has been the low rooting efficiency of the microshoots. Various treatments were tried in order to enhance rooting. Eighty-three percent of microshoots harvested between 5 and 7 weeks and treated continuously with 4.9 micromolar IBA rooted after 4 weeks, whereas <20% of microshoots harvested before 5 weeks and after 7 weeks rooted after 4 weeks of continuous exposure to IBA. Differences were also observed in rooting potentials of microshoots that had reddish brown stems rooting at a higher frequency compared to those that had green stems. We hope to translate this method to the propagation of cultivars and potential new releases.
Anjana R. Sharma, Robert N. Trigiano, Willard T. Witte and Otto J. Schwarz
Margaret W. Kirika, Jane W. Kahia, Lucien N. Diby, Eliud M. Njagi, Colombe Dadjo and Christophe Kouame
Murashige and Skoog (1962) (MS) basal salts. On the other hand, for regeneration of microshoot, the MS media was supplemented with 3% (w/v) sucrose, BAP evaluated at 2.15, 4.30, 6.46, and 8.61 mg/L, and kinetin at 2.25, 4.50, 6.75, and 9.0 mg/L in separate
Clare Bowen-O'Connor, John Hubstenberger, Dawn Van Leeuwen and Rolston St. Hilaire
Double-node microshoots of bigtooth maple (Acer grandidentatum Nutt.) were rooted in vitro on Driver-Kuniyuki Walnut (DKW) tissue culture media containing indole acetic acid (IAA). Microshoots represented six sources from three locations within Texas and New Mexico. Microshoots were placed in Phytatrays II™ containing DKW media with no plant growth regulator (DKW0) to reduce the high cytokinin levels used for shoot proliferation. Microshoots were induced to form roots for 15 days by placing them on DKW media containing IAA at 0.01, 1, 2.5, 5, 10, 15 or 20 μmol. Rooting frequency, the number of leaves and callus area were recorded every 30 days for 60 days. Rooting frequency increased up to 29% as IAA concentration increased (P= 0.004). However, as much as 71% of shoots for one of the three Guadalupe Mountain, Texas, sources rooted without auxin treatment after 30 days. The IAA concentration also affected the number of leaves per shoot (P= 0.0228) which averaged seven and callus area (P= <0.0001) which averaged 52 mm2. Average leaf size was 307 mm2. We conclude that IAA induces rooting in microshoots of bigtooth maple after 15 days of root induction. However, one source rooted without auxin treatment. The presence of callus does not interfere with root formation.
Almudena Montoliu, Aurelio Gómez-Cadenas and Rosa M. Pérez-Clemente
rooting efficiency of Carrizo citrange microshoots produced from cultures initiated from nodal explants. Carrizo citrange is a main citrus rootstock widely used in important citrus-producing areas such as Spain and California, where ≈90% of the new
Mark C. Starrett, Frank A. Blazich, Steven R. Shafer and Larry F. Grand
Selected isolates of Hymenoscyphus ericae (Read) Korf and Kernan, Oidiodendron griseum Robak, O. maius Barron, and a second O. Robak species were evaluated as inocula for in vitro establishment of micropropagated plantlets of Pieris floribunda (Pursh ex Sims) Benth. and Hook. Severity of shoot necrosis on microshoots differed for each isolate of Oidiodendron. Inoculation of micropropagated plantlets with isolates of H. ericae benefited initial shoot and root development on agar-solidified Woody Plant Medium (WPM) supplemented with sucrose and covered by a layer of autoclaved 1 peat: 1 vermiculite (v/v). Inoculation of microshoots with H. ericae or isolates of Oidiodendron did not stimulate production of adventitious roots.
Asma Alhussein Alawaadh, Yaser Hassan Dewir, Mona S. Alwihibi, Abdulhakim A. Aldubai, Salah El-Hendawy and Yougasphree Naidoo
philodendron microshoots [‘Imperial green’, ‘Imperial Red’, and ‘Imperial Rainbow’ ( Chen et al., 2012 )]. In contrast, Sreekumar et al. (2001) reported that microshoots from six philodendron cultivars rooted easily in MS medium without PGR supplementation
K.H. Al-Juboory, D.J. Williams and R.M. Skirvin
Shoots of greenhouse-grown Algerian ivy (Hedera canariensis L.) were surface disinfected and explanted on modified Murashige and Skoog (MS) medium supplemented with BA (10 μm) and NAA (2.5 μm). One month later the shoots were transferred to MS proliferation medium supplemented with TDZ (0.1 or 0.5 μm) and NAA (40 μm). An average of three microshoots developed on each stem treated with TDZ. Pruned shoots grown on MS medium supplemented with GA3 (20 μm) and BA (20 μm) branched better than unpruned shoots (3.7 vs. 1 per explant, respectively). Rooted shoots grown ex vitro grew and developed a shape suitable for commercial sale in 3 months. Chemical names used: N -(phenyl-methyl)-l H -purine-6-amine (BA); gibberellic acid (GA3); 1-naphthaleneacetic acid (NM); N -phenyl-W-1,2,3-thiadiazo-5-yl urea (Thidiazuron, TDZ).
María Victoria González, Manuel Rey and Roberto Rodríguez
A simple and reliable protocol for plant regeneration from petioles of micropropagated plants of kiwifruit [Actinidia deliciosa (A. Chev) Liang and Ferguson, var. deliciosa `Hayward'] is described. Morphogenic callus was initiated by culturing petioles taken from in vitro-propagated plants. From the media tested, Cheng's K(h) medium plus 0.1 μm IAA, 4.5 μm zeatin, and 2% sucrose was the best for callus induction, maintenance, and shoot bud formation and development. Bases of developed shoots were immersed in 5 mm IBA for 15 seconds; subsequent culture in half-strength K(h) basal medium achieved 82% rooting. Regenerated plantlets were successfully transplanted to soil with 97% survival. Chemical names used: indole-3-acetic acid (IAA); indole-3-butyric acid (IBA); 2-methyl-4-(1H-purin-6-ylamino)-2-buten-1-ol (zeatin).
Karim H. Al-Juboory, David J. Williams and Munir H. Nayfeh
How-Chiun Wu, Mei-Ling Kuo and Chia-Min Chen
phenolic browning, it is known to be a difficult-to-propagate species in vitro. As a result, unlike other economically important plant species, in vitro propagation of P. cynaroides microshoots has yet to be achieved on a commercial scale. Previous