Cellular and karyological variations in populations of green leafhopper Nephotettix virescens (Distant) in the Philippines

Issue Date

4-2001

Abstract

Populations of the green leafhopper, Nephotettix virescens (Distant), were sampled from rice fields in the Philippines (Albay, Isabela, Laguna, Nueva Ecija, and Zambales) that were infested and non-infested with tungro virus. Males were cytologically and karyologically examined, described and compared. Lacto-aceto-orcein squash preparations of the testes of all N. virescens sampled had meiocytes which followed the conventional sequence of reductional-equational divisions. The dominant gametic cells were primarily spermatocytes undergoing Meiosis I stages. In terms of the quantitative features of the meiotic cells of all male N. virescens samples, no obvious variations was detected. However, in terms of the meiotic index, the tungro-transmitting male N. virescens had mean index of 86.06% whereas non-tungro-transmitters had 81.70%. All N. virescens exhibited normal and regular meiosis. In terms of chromosome number, all N. virescens have 2n = 15, the karyotype formula is 7 II + XO. There were two types of spermatocytes: one with (7 IA) and the other with (7 IA +X), the latter was the predominant type. The mean relative lengths of diakinesis chromosomes of male N. virescens from non-tungro rice fields of five provinces did not vary significantly, while those from tungro-infested fields exhibited heterogeneous measurements, many of which were statistically varied between and among each other. Among the five different rice fields, the male N. virescens from Isabela and Nueva Ecija, exhibited significant differences in mean relative lengths of diakinesis autosomes 1, 2, 4 and 6 and X chromosomes. Chromosomes 3, 5 and 7 were stable of both tungro-vector and non-tungro-vector N. virescens.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

15

Issue

1

Page

75-82

Document Type

Article

Frequency

semi-annually

Physical Description

illustrations; tables

Language

English

En – AGROVOC descriptors

CICADELLIDAE; NEPHOTETTIX VIRESCENS; CYTOGENETICS; CYTOLOGY; KARYOLOGY; PHILIPPINES

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