First detection of endopolyploidy in tapetal cells and chromosomal anomalies in meiocytes of Viola pilosa cytotypes (2n=20) from Pir Panjal (Himalayas).

The nine Viola pilosa Blume populations studied from Pir Panjal contained 20 chromosomes. This count is not reported so far in Indian populations. Currently, comparison of tapetal and meiotic cells revealed the existence of synchrony in different developmental phases. Young tapetal cells at prometaphase co-occurred with the pollen mother cells (PMCs) at diakinesis to metaphase, mature tapetal cells with disintegrated chromatin material co-occurred with tetrads and no tapetal cells were found at mature pollen stage. Cytological studies in young tapetal cells revealed most of these to be endopolyploid, with each having 40 chromosomes. While outnumbering somatic cells contained clear 40 chromosomes which seemed to be the outcome of endomitosis, a sizeable number of cells possessed 40 sticky chromosomes at metaphase. Later chromosomes are likely to form restitution nucleus. Mature tapetal cells, occurring singly/cytomictically connected (3.2-26.31%) or showing coalescence (10.5-22.8%), did not contain recognizable chromosomes. Instead, they were characterized by disintegrated nuclear content. Further, meiotic studies revealed that the present population contained all/outnumbering euploid cells (2n=20); many of which exhibited nearly regular behaviour. However, 6.5-26.9% meiocytes of eight populations and 47% cells of P-Khe population depicted aneuploidy/contained quadri-octavalents, with per cent pollen viabilities of these ranging from 38.6 to 49.9. Going by the normal tapetal development in V. pilosa, existence of various chromosomal anomalies seems to have accounted for the reduction in gametic fertility of this taxon.

Assessment of variability among morphological and molecular characters in wild populations of mint [Mentha longifolia (L.) L.] germplasm.

Mentha longifolia is an important medicinal and aromatic perennial herb that exhibits wide distribution range from sub-tropical to temperate regions. In the present study, agro-morphological traits and genetic differences in 19 different populations of M. longifolia were studied to evaluate the level and extent of its diversity. Analysis of variance (ANOVA) showed that the different phenotypic characters show considerable differences among various populations and was significant at p < 0.05. Molecular diversity analysis performed by using arbitrary amplified eleven ISSR primers generated a total of 121 amplicons that range within the size of 200-2500 base pairs (bp). Each primer on average generated 11 amplicons with percentage polymorphism being 100. The analysis of molecular variance (AMOVA) showed more (64%) among population genetic diversity and less (36%) within the populations. Greater genetic differentiation (Gst = 0.6852) among these populations occurs due to low gene flow (Nm = 0.2297) and greater habitat variability. Geographic and genetic distances were positively correlated according to Mantel's test. In order to remove any kind of biases, we used R software to perform cluster and redundancy analysis to analyse the extent of relatedness among studied populations. In terms of morphological and molecular aspects, the populations were grouped into four and five clusters respectively based on hierarchical clustering method. The results demonstrated that M. longifolia displays a great degree of morphological and genetic variation and can be utilized in breeding, genetic improvement, and gene bank conservation programmes in future.