Introduction of Clean Plants into Tissue Culture: Temperate Crops
Introduction of Clean Plants into Tissue Culture: Temperate Crops
Gayle M. Volk, USDA-ARS National Laboratory for Genetic Resources Preservation, 1111 S. Mason St., Fort Collins, Colorado 80521<EMAIL_ADDRESS>Jeanine DeNoma, USDA-ARS National Clonal Germplasm Repository, 33447 Peoria Road, Corvallis, Oregon 97333.
Kim Hummer, USDA-ARS National Clonal Germplasm Repository, 33447 Peoria Road, Corvallis, Oregon 97333.
Katheryn Chen, Department of Soil and Crop Sciences, Colorado State University, 307 University Ave., Fort Collins, Colorado 80523.
Outline
- Introduction to plant tissue culture and its value for genebank conservation
- Selection of plants for introduction into tissue culture
- Surface sterilization
- Endophyte assessment
- Tissue culture establishment, subculture, and multiplication
- References
- Additional information
- Acknowledgments
1. Introduction to plant tissue culture and its value for genebank conservation
Some genebank collections are maintained in tissue culture, which may allow them to be more easily distributed and backed-up at a secondary location. These collections require personnel to maintain the cultures and may be susceptible to somaclonal variation (Bairu et al., 2011). In some cases, collections can be placed into reduced-temperature storage to prolong the times between culture transfers, as described in the chapter “Reduced-Temperature Storage of Temperate Crops in Tissue Culture“. Often, plants are introduced into tissue culture from field, greenhouse, or screenhouse conditions. These plants may have surface contamination or endophytic contamination that should be eliminated during the introduction process.
This chapter describes and demonstrates methods that have been successful for introducing clean mint and strawberry plants from greenhouse conditions into tissue culture. USDA National Plant Germplasm Collections for both of these crops are maintained in greenhouses at the National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon. Tissue cultures of these materials have been maintained in reduced-temperatures for medium-term storage, and have also provided the source plants for shoot tip cryopreservation, as described in the chapter “Mint Shoot Tip Cryopreservation“.
2. Selection of plants for introduction into tissue culture
It is important to select plant materials for introduction into tissue culture that are most likely to be free of endophytes and surface contamination. It is generally preferable to use source plants that have young, actively growing tissue in greenhouse or screenhouse conditions (Fig. 1, 2). Alternate source material, such as young plant tissue from the field or even cuttings of winter budwood that are forced indoors, may be substituted if healthy greenhouse or screenhouse material is not available.
Actively growing shoots or runners of greenhouse-grown plants are harvested with tools that are dipped in 20% bleach (1.2% sodium hypochlorite) and rinsed with water between each cut.