Seed Physiological Studies in Six Wild Prunus Species of Indian Himalayas: Implications for Their Cryobanking

Wild Prunus species represent important genetic resources in terms of their potential as source material for domestication as well as their applicability in improving commercially important fruits. Due to their niche specific nature and narrow adaptability, threats to their existence in advent of climate change and population pressure are now coming into reality. Urgent attention is required to conserve these temperate wild species in present times before their valuable diversity declines. In present studies germination methods for seeds and excised embryonic axes in six wild Prunus species namely Prunus armeniaca L., Prunus mira Koehne, Prunus cornuta (Wall. ex Royle) Steud., Prunus jacquemontii Hook.f, Prunus nepalensis Hook. f. and Prunus cerasoides Buch.-Ham. Ex D. Don. collected from North-Western Indian Himalayas were standardised using various substrata and pre-treatments like chemicals and cold stratification. Physical and physiological dormancy was observed in Prunus armeniaca, P. mira, P. cornuta, P. jacquemontii and P. cerasoides and dormancy breaking methods were standardized. Cold stratification of seeds at − 4 °C and removal of kernel coat significantly reduced the germination time and increased the germination percentage in five species of Prunus. Desiccation and freezing tolerance of seeds and axes was studied for their amenability to cryopreservation for long term preservation. Results confirmed the orthodox seed storage behaviour for all the Prunus species except Prunus nepalensis which proved to be highly recalcitrant due to lack of dormancy and with high desiccation sensitivity. Seeds and axes of all the five orthodox seed species. Survived liquid nitrogen exposure. Use of new protocols namely vitrification and vacuum infiltration vitrification with embryonic axes of Prunus nepalensis also failed to yield survival after liquid nitrogen exposure. Further investigations are required for safe handling and conserving germplasm of Prunus nepalensis where complimentary methods of field genebank can be adopted.