Meiotic chromosomal behaviour of Artemisia amygdalina Decne: A critically endangered medicinal plant, endemic to the North-western Himalaya.

• The diploid chromosome number (2 n =18) in A. amygdalina has been reported for the first time from North-western Himalaya, marking a previously unrecorded finding. • Detailed analysis of meiotic behaviour, showed the occurrence of various chromosomal aberrations in three distinct populations. • The effect of various meiotic abnormalities on the frequency of chromosomal aberrations, pollen sterility, and abnormal microspore formation across the populations has been documented. • Comparison of meiotic behaviours among populations at different altitudes revealed significant differences and potential environmental influences. The limited geographic distribution of endemic species renders them more susceptible to extinction risks stemming from a myriad of factors. One such factor could be meiotic constraints, which may directly or indirectly impact the reproductive success of the endemic plant species. Thus, comprehensive research on meiotic behaviour is essential for implementing species conservation measures. This study represents the first report on the male meiotic behaviour of Artemisia amygdalina Decne., a critically endangered endemic medicinal plant species of the Kashmir Himalaya. We procured the plant material from three different locations in the Kashmir Himalaya, and the chromosome number of the species from all sites was found to be 2 n =18 (x = 9, n = 9), indicating its diploid nature. Various types of chromosomal abnormalities were found in these populations, including stickiness, univalents, out-of-plate bivalents, laggards, bridges, disturbed telophase, micronuclei, abnormal pollen grains formation and seed set formation. The overall percentage of chromosomal abnormalities varied among the populations, from 8.58 % to 25.16 %. Pollen sterility also varied among different populations, with maximum pollen sterility of 23.21 % and a minimum of 5.96 % across populations. The present findings will not only help in updating the chromosome atlas with the addition of a new report on chromosome number but also contribute to the understanding of the reproductive success of A. amygdalina. Further ecological and reproductive studies can facilitate the creation of effective management and conservation strategies for this species. [ABSTRACT FROM AUTHOR]