New insights into the phenology, genetics and breeding system of critically endangered Nardostachys grandiflora DC

Abstract

The critically endangered Nardostachys grandiflora DC is a highly renowned medicinal and aromatic plant of the Western Himalayan region, traditionally used in treating heart palpitations, convulsions, epilepsy and insomnia, as well as being a source of aromatic oil used as incense, flavoring agent and in quality perfumes. This species is on the verge of extinction due to over-exploitation and habitat destruction and needs immediate preventive measures. Despite being essential for domestication, there have been few studies of the natural variation, breeding and genetic system of this species possibly due to its remote location and sparse populations. The present study has revealed that N. grandiflora, which is restricted to specific ecological niches in high alpine regions 3000–5000 m asl, is under stress due to its infrequent flowering nature, which limits generation of new variation, although some intra-population variability with regard to lamina margin (dentate and wavy) and type of stigma (capitate and trilobed) were observed. This limited variability prevents the species from colonizing new niches, as it mostly multiplies through rhizome ramets. Several interesting features have also been revealed, e.g. presence of bicolpate, tricolpate, tetracolpate and pentacolpate pollen grains as well as isobilateral, decussate and tetrahedral types of tetrad within the same or in different flowers. This study also establishes a new diploid chromosome number (2n = 78), the plant’s genomic allohexaploidy, up to 58% cross pollination; protoandry, its infrequent flowering nature, a high pollen ovule ratio of 6135 ± 327.86 per flower and poor seed set.

Keywords:

• Nardostachys grandiflora
• spikenard
• critically endangered
• medicinal and aromatic
• temperate Himalaya
• pollen grains

Acknowledgements

The study was conducted under All India Co-ordinated Research Project (AICRP) on Medicinal, Aromatic Plants and Betelvine (MAPB) of Indian Council for Agriculture Research (ICAR), New Delhi, and financial support from ICAR is acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.