Author
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Reed, Barbara |
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Submitted to: In Vitro Cellular and Developmental Biology - Plants
Publication Type: Abstract Only Publication Acceptance Date: 1/20/2006 Publication Date: 1/20/2006 Citation: Reed, B.M. 2006. Medium-term in vitro storage of pear (pyrus l.) germplasm. In Vitro Cellular and Developmental Biology - Plants. 42:23-A. Interpretive Summary: The United States Department of Agriculture, Agricultural Research Service National Clonal Germplasm Repository at Corvallis, Oregon (NCGR), preserves genetic resources for Pear (Pyrus L). More than 1800 Pear clones and more than 300 seed accessions representing the 26 species are maintained in this genebank. The main collections are held as trees in the field with micropropagated plantlets (tissue culture) as a secondary backup and more than 100 cryopreserved as small shoot tips in liquid nitrogen. The in vitro collection includes about 200 accessions. Micropropagated plantlet storage is a constant 4°C with 12 h of low light. Pear accessions stored at NCGR from 2001 to 2005 were monitored and the length and variability of storage were evaluated. Among the P. communis (European pear) accessions, five wild collected European pear accessions stored for an average of 26 ± 2.4 mo, seven types of ‘Bartlett’ pear for 3.5 years (42.7 ± 12.5 mo), four types of ‘Doyenne du Comice’ for 19.8 ± 9.9 mo, and eight ‘Old Home x Farmingdale’ types averaged over 4 years (50 ± 13 mo) in cold storage. Pear species from other regions also stored very well under standard conditions. Six P. amygdaliformis accessions averaged 38.7± 11 mo, eight P. calleryana 36.7 ± 5 mo, and three accessions each of P. cordata 44.6 ± 10 and P. cossonii 33.7± 15.5 mo. The longest storing accession was P. gharbiana No. 4 which was held for over 8 years (100 mo) before requiring repropagation. Technical Abstract: The United States Department of Agriculture, Agricultural Research Service National Clonal Germplasm Repository (NCGR) at Corvallis, Oregon, preserves genetic resources for pears (Pyrus L). More than 1800 clones and more than 300 seed accessions in 26 Pyrus species are maintained in this genebank. The main collections are held as trees in the field. The backup collection includes about 200 in vitro and more than 100 cryopreserved accessions. The in vitro collection is stored at a constant 4°C with 12 h of low light following one week of cold acclimation. Data on plant health and length of storage was taken for Pyrus accessions stored at NCGR from 2001 to 2005. Multiple storage cycles were evaluated for 66 accessions and a single cycle for 187 accessions. The mean storage time for 253 Pyrus accessions was 30.4 ± 12 mo. Many accessions varied with storage cycle, probably due to medium preparation or handling of shoots. Among the European pear (P. communis) accessions, five wild collected accessions stored for an average of 26 ± 2.4 mo, seven clones of ‘Bartlett’ pear for 3.5 years (42.7 ± 12.5 mo), four clones of ‘Doyenne du Comice’ for 19.8 ± 9.9 mo, and eight ‘Old Home x Farmingdale’ clones averaged more than 4 years (50 ± 13 mo) in cold storage. Pear species stored very well under standard conditions. Six P. amygdaliformis accessions averaged 38.7± 11 mo, eight P. calleryana 36.7 ± 5 mo, and three accessions each of P. cordata 44.6 ± 10 and P. cossonii 33.7± 15.5 mo. The longest storing accession was P. gharbiana No. 4 which remained in storage for over 8 years before requiring repropagation. A few cultivars consistently stored for short times, but no particular trends were observed. Storage at 4° C with a photoperiod appears to be excellent for most Pyrus germplasm. |
