Karyomorphometrical analysis of Emilia sonchifolia (Linn) DC. (Asteraceae: Senecioneae) depicts aneuploidy incidence in diploid populations
2014
Yamuna, Aju Baburaj | Radhakrishnan, Rajalakshmi
The present investigation concerns detailed karyomorphometrical studies of seven accessions of Emilia sonchifolia collected from different regions of Kerala. Karyotype analysis showed very remarkable results. Diploid individuals with 2n = 10 showed 5 homologous pairs of chromosomes, but plants with accession numbers 3 (ES3) and 7 (ES7) collected from Murukkumpuzha and Palakkad respectively, showed 2n = 8 with 3 pairs of homologous chromosomes and 2 non homologous chromosomes indicating aneuploidy level 2n-1-1 (double monosomic). The plants from Parasala showed complete loss of one set of chromosome and attain the condition 2n-2 (nullisomic). Plants from Idukky with accession number 6 (ES6) showed a non-homologous chromosome in addition to 4 homologous pairs of chromosomes and the chromosome number was 2n = 9 (monosomic). This was a new count for E. sonchifolia. This study indicates that levels of ploidy in E. sonchifolia depend on its occurrence in different geographical regions. Plants presented with aneuploidy in this study (accession numbers 3, 4, 6 and 7) showed distinct morphological features such as reduced height, reduced number of florets per capitulum etc. The occurrence of aneuploidy in E. sonchifolia needs further investigation in relation to its geographical distribution.
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