Karyotype of potato tuber moth, Phthorimaea operculella (Zeller) – first report from India

Abstract

In the present study, the karyotype of potato tuber moth, Phthorimaea operculella (Zeller) was studied from Himachal Pradesh, India. The diploid chromosome number (2n) in this moth species was found to be 58. The chromosomes at diplotene stage showed variation in size but at metaphase stage, these appeared almost of similar size. The total bivalent complement length was 63.37 μm ± 0.93 S.E. The longest chromosome was 4.69 μm ± 0.09 S.E. in the length while the shortest chromosome was 1.12 μm ± 0.03 S.E. The percentage relative length of chromosome ranged from 1.77 ± 0.05 S.E. in the shortest chromosome to 7.40 ± 0.19 S.E. in the longest chromosome. This is the first report on the karyotype of this species from India. Meiotic divisions were found clearly in testis preparation. In diplotene stage, 29 bivalents were clearly visible showing high degree of condensation and during metaphase I of male meiosis, these 29 bivalents were maximally condensed. In early anaphase I, the homologues started separating from each other. Two types of spermatozoa, apyrene and eupyene were also observed.