RESULTS: In general, the genetic diversity decreased from Costa Rica towards the north (Honduras) and south-east (Colombia). Principle coordinate analysis (PCoA) showed a single cluster indicating low divergence among palms. The phylogenetic tree and STRUCTURE analysis revealed clusters based on country of origin, indicating considerable gene flow among populations within countries. Based on the values of the genetic diversity parameters, some genetically diverse populations could be identified. Further, a total of 34 individual palms that collectively captured maximum allelic diversity with reduced redundancy were also identified. High pairwise genetic differentiation (Fst > 0.250) among populations was evident, particularly between the Colombian populations and those from Honduras, Panama and Costa Rica. Crossing selected palms from highly differentiated populations could generate off-springs that retain more genetic diversity.
CONCLUSION: The results attained are useful for selecting palms and populations for core collection. The selected materials can also be included into crossing scheme to generate offsprings that capture greater genetic diversity for selection gain in the future.
HISTORY: Hampson (1900) included a total of ten species: Nishada niveola Hampson, 1900, Nishada syntomioides (Walker, 1862), Nishada impervia (Walker, 1865), Nishada marginalis (Felder 1875), Nishada tula Swinhoe, 1900, Nishada nodicornis (Walker 1862), Nishada rotundipennis (Walker 1862), Nishada flabrifera Moore, 1878, Nishada sambara (Moore 1859) and Nishada xantholoma (Snellen 1879). Swinhoe (1902) and Hampson (1911) then described two new species, Nishada melanistis and Nishada brunneipennis, respectively, followed by Rothschild (1912, 1913) who described a further seven new species, Nishada brunnea, Nishada flavens, Nishada testacea, Nishada griseoflava, Nishada fuscofascia, Nishada louisiadensis and Nishada aurantiaca, bringing the total to 19 species. Strand (1922) catalogued only 13 of these species in Nishada, transferring N. brunnea and N. fuscofascia to genus Scoliacma Meyrick (1886); N. testacea, N.griseoflava and N. louisiadensis Rothschild to Eilema Hübner (1819) and synonymising N. flavens with N. sambara. Next, Matsumura (1927) described N. formosibia, followed by two more species, N. aureocincta Debauche, 1938 and N. benjaminea Roepke, 1946. Holloway (2001) synonymised N. nodicornis with N. rotundipennis and added the description of a new subspecies, Nishada chilomorpha adunca Holloway, 2001 from Borneo, indicating a distributional range as far as North East India. The nominotypical subspecies, N. c. chilomorpha was suggested to be restricted to its type locality of Java. Bucsek (2012) added Nishada cameronensis, Dubatolov & Bucsek (2013) described Nishada schintlmeisteri and Bucsek (2016) described Nishada temenggora. So, at present, Nishada comprises19 species, of which three are known from India (Singh et al. 2014). Herein, we describe one further species, Nishada pseudochilomorpha Joshi & Singh sp. nov., from Jatinga (Assam, India). In addition, new distributional records are reported for N. flabrifera.