Spectrum of chromosome associations in synaptic variants of Mantisia wengeri (Zingiberaceae) - An endemic, critically-endangered and probable inter-specific hybrid

Male meiotic studies have been conducted in a synaptic variant of Mantisia wengeri, a critically-endangered and endemic rhizomatous herb of north-east India. Studies reveled synaptic variation of the chromosomes and the only 10% of pollen mother cells (PMCs) showed the normal meiotic pattern, while 90% of PMCs demonstrated abnormal meiotic behavior by showing a spectrum of chromosome associations. A total of 747 bivalents along with a good number (506) of univalents were recorded with moderate chiasma frequency (14.94±9.20) with the terminalization coefficient of 0.82 only. About 40% of PMCs showed anomalous distribution patterns of chromosomes, including unequal distribution and/or presence of laggards in the form of univalents/bivalents resulting in low pollen-stainability (57.33±8.40). A comparative analysis of synaptic behavior of chromosomes during meiosis in M. wengeri and M. spathulata was carried out. The role of genomes vis-avis the chromosome behavior of M. spathulata and M. radicalis in the development of the crossbreed M. wengeri has been discussed. Unbalanced chromosome associations with partial synaptic failure are considered as causative factors for sustained diversity in critically-endangered and endemic genus Mantisia.