INADVERTENT SELECTION FOR UNWANTED MORPHOLOGICAL FORMS DURING MICROPROPAGATION ADVERSELY AFFECTS FIELD PERFORMANCE OF EUROPEAN RHUBARB (RHEUM RHAPONTICUM)

Rhubarb has been successfully micropropagated for many years, producing field performance comparable to conventionally propagated material and widely accepted by breeders and growers.
However, a novel breeding line lacking late summer dormancy, has shown unpredictable field performance following micropropagation.
An investigation over two growing seasons shows that the plantlet size at transplanting plays a significant role in subsequent growth and performance, with 75% of smaller plantlets failing survive two seasons compared to losses of less that 12% for larger transplants.
Theses smaller subjects had developed an aberrant, recumbent morphology in the field making them susceptible to lethal frost and disease injury.
The absence of vertical architecture in the canopy is associated with high leaf number and unacceptably thin petioles.
Commercially micropropagated material, from two sources, produced large numbers of transplants with the aberrant morphology.
Laboratory micropropagation, where the number of culture passages and plantlets produced was low, did not produce the aberrant forms.
Recumbent plantlets held in a glasshouse environment subsequently developed an acceptably vertical architecture.
This paper considers alterations to the micropropagation process and husbandry that need to be considered when novel plants, valuable for modified growth, and field performance are multiplied on a commercial scale.

I International Symposium on Acclimatization and Establishment of Micropropagated Plants

Y. Zhao, B.W.W. Grout, C. Crisp

Rhubarb, field performance, micropropagation, morphological variation, survival

https://doi.org/10.17660/ActaHortic.2003.616.42