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United States Department of Agriculture

Agricultural Research Service

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Vegetatively-Propagated Germplasm
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Strawberry meristems

Vegetatively-propagated germplasm is used to retain the exact genetic line (genotype) of a crop, such as a Red Delicious apple. Germplasm is distributed as cuttings or explants rather than seeds.  NPGS collections of vegetatively-propagated crops are maintained in field plantings which are vulnerable to insects, diseases and environmental challenges.  Frequent regeneration – for example garlic is replanted every year -- increases the vulnerability and cost of the collection.  One method to back-up vegetatively-propagated germplasm collections uses tissue culture, where plants are grown and maintained in a sterile environment containing nutrients, a carbon source and vitamins.   Cryopreservation of very small (1-2mm) meristematic shoot tips or dormant winter buds in liquid nitrogen (-196°C) presents an alternative method for long term storage that reduces the cost of maintaining growing plants.  Protocols for tissue culture and cryoprotection are crop and genotype dependent, with few protocols available for NPGS germplasm.  NCGRP has been developing and implementing cryopreservation methods for vegetatively- propagated crops for almost two decades. 

See protocols for cryopreservation methods used for shoot tips and dormant buds at NCGRP

Number and genera of vegetatively-propagated plants in long-term cryopreservation at NCGRP (as of September 27, 2010).

Taxon

MS

BD

1In progress

2Canadian GRP

Total # of accs.

Allium sativum

51

 

21

 

72

Corylus

4

 

 

 

4

Cydonia

1

 

 

 

1

Cynodon

25

 

 

 

25

Fragaria

73

 

 

 

73

Humulus

35

 

 

 

35

Ipomoea

9675

 

5

 

68

Lolium

15

 

 

 

15

Malus

 

2,233

28

302

2,563

Mentha

44

 

 

 

44

Musa

 

 

2

 

2

Prunus

 

50

25

 

75

Pyrus

151

 

1

 

152

Ribes

64

 

2

 

66

Rubus

100

 

 

 

100

Salix

 

17

10

 

27

Solanum

63

 

 

 

63

Zoysia

5

 

 

 

5

Total # of accs.

657

2,300

92

302

3,351

1Cryopreserved but viability testing in progress
2samples from the Canadian Genetic Resources Program
MS-meristematic shoot tips
BD- dormant winter buds

 


Last Modified: 10/25/2010
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