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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #135068
Title: IMPROVING IN VITRO PLANT REGENERATION FOR 'MARION' BLACKBERRY

Author
item MENG, RENGONG - OSU
item CHEN, TONY - OSU
item Finn, Chad

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2003
Publication Date: 4/1/2004
Citation: Meng, R., Chen, T.H., Finn, C.E. 2004. Improving in vitro plant regeneration for 'marion' blackberry. Hortscience. 29(2)p.316-320.

Interpretive Summary: 'Marion' is the most important blackberry cultivar in the world primarily due to its outstanding processing characteristics. Genetic engineering may offer an approach to improve the cold hardiness of 'Marion' without sacrificing its superior flavor and processing quality. As a successful in vitro regeneration is the prerequisite for genetic transformation, a series of experiments were conducted to optimize the conditions for in vitro regeneration for 'Marion'. Parameters studied included types, and concentrations of plant growth regulators, and the duration of treatment with these regulators, source of plant material, and medium formulations. The highest shoot regeneration rate (69.6%) and highest number of shoots (5.1 shoots/explant) were obtained under the following conditions: stock plants were pretreated with TDZ (1mM) for three weeks, followed by leaf explants dark pretreatment for one week on the regeneration medium (WPM with 5mM BA and 0.5mM IBA). After dark treatment, regeneration plates were placed under 16-hour photoperiod at light intensity of "50 mmol×m-2×s-1 at 23°C + 2°C for 4 weeks. This research has developed a successful regeneration system for 'Marion' blackberry. Further work will fine-tune this system and move on to transformation.

Technical Abstract: A series of experiments were conducted to optimize the in vitro plant regeneration conditions for 'Marion' blackberry. Parameters studied included types (three cytokinins: BA, kinetin, and zeatin; four auxins: IBA, IAA, NAA, and 2,4-D) and concentrations of plant growth regulators, types of explants (leaf and petiole), medium formulations (MS, WPM and BMM), orientation of explant in contact with medium, TDZ pretreatment of in vitro grown stock plants (zero to six weeks), leaf explant form, leaf explant orientation, and artificial wounding of explants. The highest shoot regeneration rate (69.6%) and highest number of shoots (5.1 shoots/explant) were obtained when stock plants were pretreated with TDZ (1 mM) for three weeks, followed by culturing leaf explants on the regeneration medium (WPM with 5 mM BA and 0.5 mM IBA) for one week in the dark. After 1 week of dark treatment, explants were incubated under 16-hour photoperiod at light intensity of "50 mmol×m-2×s-1 at 23 °C + 2 °C for 4 weeks.