Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 8, 2005
Publication Date: December 2, 2005
Citation: Reed, B.M., Schumacher, L.D., Wang, N., D Achino, J., Barker, R.E. 2005. Cryopreservation of bermudagrass germplasm by encapsulation dehydration. Crop Science [serial online]. 46:6-11 (2006). Interpretive Summary: Many types of bermudagrass are vegetatively propagated and must be maintained as growing plants for preservation. Tissue-culture conservation through cryopreservation in liquid nitrogen at -196°C provides a secure alternative to duplicated greenhouse-grown collections. A diverse group of bermudagrass was tested for storage by a new technique. This involves placing the tiny growing portions of the plant into a bead of gel and drying it to a low moisture content before storing in liquid nitrogen. Seventeen of the grasses (74%) had good growth after removal from the liquid nitrogen while the rest had low regrowth. Thirty shoot tips of each of 34 bermudagrasses are now held in liquid nitrogen storage at the National Clonal Germplasm Repository (NCGR) Corvallis and 50 additional cryopreserved shoot tips are held at the National Center for Germplasm Resources Preservation (NCGRP) in Fort Collins, Colorado.
Technical Abstract: Genetic conservation of vegetatively-propagated grasses requires intensive care of pot cultures or carefully separated field plots. Even with intensive care, there is high risk of mechanical contamination and loss of plants to biotic and abiotic stresses. Medium and long-term storage of this germplasm would be more cost effective and provide a backup for field or greenhouse germplasm collections. Cynodon sp. L. (bermudagrass) germplasm is mostly stored as growing plants. Long-term storage in liquid nitrogen could provide a secure backup for these collections. We evaluated a diverse group of Cynodon species and selections for long-term storage in liquid nitrogen at '196 'C. The encapsulation-dehydration (E-D) cryopreservation protocol was effective for most genotypes tested when combined with a 1 to 4-wk cold acclimation period and dehydration to 20 to 22% moisture before exposure to liquid nitrogen. Recovery of shoot tips cryopreserved following E-D ranged from 20% to 90%. Seventeen of the 23 accessions (74%) had greater than 40% regrowth. Thirty encapsulated shoot tips of each of 34 Cynodon accessions are now held in liquid nitrogen storage at the National Clonal Germplasm Repository (NCGR) Corvallis and 50 additional cryopreserved shoot tips are held as a base collection at the USDA-ARS, National Center for Germplasm Resources Preservation (NCGRP) in Fort Collins, Colorado.