Cellular and chromosomal variations in populations of green leafhopper, Nephotettix virescens (Distant) sampled from tungro-infested and non- tungro-infested ricefields in Bay, Laguna

Date

10-1995

Degree

Bachelor of Science in Biology

Major Course

Major in Cell Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Adelina A. Barrion

Abstract

Hannah Whilma D. Lacar, University of the Philippines Los Banos. October 1995. -CELLULAR AND CHROMOSOMAL VARIATIONS IN POPULATIONS OF GREEN LEAFHOPPER NephoieUix virescens (Distant) SAMPLED FROM TUNGRO-INFESTED AND NON-TUNGRO-INFESTED RICEFLELDS IN BAY. LAGUNA." An undergraduate thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Biology, major in Cell Biology. Institute of Biological Sciences, College of Arts and Sciences.

ADVISER: Dr. Adelina A. Barrion

Natural populations of green leafhopper, Nephotettix virescens (Distant), which were collected from tungro-infested and non-tungro-infested rice fields in Bay, Laguna, were fixed in freshly prepared farmer's solution, and preserved in 70% ethanol. Squash preparations of testes were stained with 2% lacto-aceto-orcein and observed under the compound microscope. Meiotic indices of the two populations were significantly different. Meiotic index suggesting the reproductive potential was significantly higher in N virescens from tungro-infested ricefield (86.5%) than those from non-tungro-infested ricefield (82.8%). Chromosome number was 2n=15 (71lA + XO) [male] and (7IIA + XX) [female]. Average lengths of diakinetic chromosomes ranged from 1.56 to 6.36 u in GLH from tungro-infested ricefield and 1.54 to 5.85 u in GLH sampled from non-tungro-infested ricefield. N virescens from tungro-infested ricefield possess longer autosomes I, II, IV while N virescens from non-huigro-infested ricefield possess longer autosomes DI, V, VI and VII. Sex chromosome was similar in both populations. Secondary spermatocytes underwent four sequential differentiation stages prior to sperm cell formation. Stage 1 cells were circular in shape, stage 2 cells had two pointed ends and a wider body, stage 3 cells had the same feature as those in stage 2 but more elongated and stage four celld had a rounded head and a pointed tail, for locomotion. Spermatids and spermatozoa of N. virescens from tungro-infested ricefield was significantly smaller than those from non tungro-infested ricefield. Features of meiotic divisions were similar in both populations.Results from the study led to the conclusion that populations of N. virescens from tungro-infested ricefield were cellularly and chromosomal lengths, relative lengths and cellular dimensions of spermatids and spermatozoa.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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