Karyotype, Male Meiosis, and Pollen Features of <i>Barleria</i> (Acanthaceae): A Wild Ornamental From India

Barleria is a palaeotropical genus of herbs, shrubs, and rarely climbers or trees. We investigated the karyotypes and male meiosis of 12 and 13 species, respectively, for the first time. Mitotic metaphases revealed two chromosome counts, 2n = 40 and 2n = 44. Chromosomes had median (m), submedian (sm), and subterminal (st) region centromeres. The total haploid chromosome length (TCL) ranged from 78.95 µm (Barleria sahyadrica) to 37.80 µm (B. nitida). Dispersion index differentiated the species into two groups, one with lower (3.40-4.79) and the other with higher (6.63-12.87) values. Principal component analysis based on six karyological parameters, namely base number (x), 2n, TCL, coefficient of variation of chromosome length, coefficient of variation of centromeric index, and mean centromeric asymmetry, exhibited three clusters. Cluster I included species of the subgenus Barleria. Cluster III had species of the subgenus Prionitis section Somalia. Cluster II comprised species of the subgenus Barleria and the subgenus Prionitis section Prionitis (B. sahyadrica). Pollen grains were oblate spheroidal or distinctly three-lobed, tri-brevicolporate with honey-combed tectum. Our analyses revealed karyological relationships among the investigated species and also provide raw data to breeders interested in horticultural applications of Barleria for accomplishing interspecific hybridization.