Ex situ conservation of strawberry ( Fragaria spp.) germplasm in ICAR-NBPGR

Strawberry (Fragaria spp.), belonging to family Rosaceae, is a 'potential' crop in India. It is a vegetatively propagated perennial crop where good quality fruiting varieties are in demand by farmers. Good quality germplasm is required by breeders for crop improvement purposes. In addition, four species of Fragaria occur wild in India. Indian Council of Agricultural Research-National Bureau of Plant Genetic Resources (ICAR-NBPGR), is actively involved in the ex situ conservation of strawberry germplasm. Largely, Fragaria germplasm is being maintained in the field genebanks at Regional Station, Bhowali in the western Himalayan state Uttarakhand. Since, the field-grown plants are exposed to pests, pathogens and natural vagaries, in vitro conservation of germplasm was emphasized as a complementary method. Theprotocols for in vitro conservation were developed for slow growth methods such as at low temperature storage and for normal growth conditions. Cultures were raised from shoot tips and runners from field genebank grown plants to have true-to-type accessions. As a safety duplicate, about 80 accessions are being maintained in the In Vitro Genebank of ICAR-NBPGR including exotic accessions procured from National Clonal Repository, Corvallis, Oregon, USA, after testing. At normal growth conditions (25 +/- 2 degrees C), the average subculture period ranges from 6 to 8 months, while at low temperature (<10 degrees C) selected 25 accessions could remain viable for more than 12 months. A total of 69 accessions were virus-indexed using commercially available antiserum kits against six strawberry associated viruses. For long-term conservation of virus-indexed germplasm, encapsulation-dehydration and vitrification methods of cryopreservation were applied on in vitro shoot tips of F. vesca. At least 20-30% post-thaw recovery was recorded. The in vitro conserved rooted plants were acclimatized and transferred to field genebank at Regional Station Bhowali. Tissue Cultured plants were morphologically similar to mother plants when observed in field.