Cytogenetics and isozyme polymorphism of the rice black bug, Scotinophara sp. (Coarctata group) (Hemiptera: Pentatomidae), sampled from the rice fields at the Bicol region
Date
4-2007
Degree
Bachelor of Science in Biology
College
College of Arts and Sciences (CAS)
Adviser/Committee Chair
Adelina A. Barrion
Abstract
Cytogenetic and electrophoretic investigations were conducted on the male rice black bugs (RBB), Scotinophara sp. (Coarctata Group), sampled from five (5) areas of the Bicol Region, namely: San Roque, Sangay, Camarines Sur; Tulangan, Matnog, Sorsogon; Bagacay, Gubat, Sorsogon; Balading, Tobaco, Albay; and Nagas, Tiwi, Albay. Testes of the Carnoy's fluid-fixed males were extracted and macerated in lacto-aceto-orcein to reveal the spermatogenetic cells during the first and second meiotic divisions. All stages of the reductional and equational meiosis were observed. The most frequently encountered meiotic stage was Prophase 1 (47.9%). Meiotic indices of Scotinophara sp. (Coarctata group) ranged from 69.4 to 83.8% and the average index was 79.1%. The average actual lengths of the Pachynema chromosomes ranged from 0.59. m to 1.37 . m and the average relative lengths ranged from 0.09 to 0.21. Diakinesis chromosomes had average actual lengths of 0.25 . m to 0.795 . m and the average relative lengths ranged from 0.07 to 0.22. The spermatocytes of the testicular cells showed the holokinetic chromosomes of Scotinophara sp. At Diakinesis, the haploid number of homologous chromosomes was seven (7). The smallest, heterochromatic, unpaired chromosome was the sex (X) chromosome. Thus, the karyotype of the heterogametic male Scotinophara sp. is 2n (. ) =12 Autosomes (A) or 12A+X producing two types of sperms, the n=7 consisting of 61A+X and n=6 or 61A only. Hemolymphs of 100 male RBB's (20 from each locality) were subjected to starch gel electrophoresis. The three enzyme systems considered were acid phosphatase (ACPH), alkaline phosphatase (ALPH), and esterase (EST).The populations were designated as: San Roque, Sangay, Camarines Sur (Locality 1); Tulangan, Matnog, Sorsogon (Locality 2); Bagacay, Gubat, Sorsogon (Locality 3); Gadgaran, Mamog, Sorsogon; Balading Tobaco, Albay (Locality 4); and Nagas, Tiwi, Albay (Locality 5). A total of 8 isoloci (ACPH-1, ACPH-2, ALPH-1, ALPH-2, EST-1, EST-2 AND EST-3) were identified. Monomorphic isoloci present in all localities were only observed in the ALPH-3 isolocus while polymorphic isoloci present in all localities were observed in ACPH-1. Genetic identity and genetic distance values computed show that there is high degree genetic similarity when comparing Localities 2 and 3. Measures of genetic variation reveal the highest mean of heterozygosity in Locality 3 implying that the RBB's in the population are more genetically diverse and have the higher capacity to contribute more chances of variation to next generation of RBB's.
Language
English
Location
UPLB Main Library Special Collections Section (USCS)
Call Number
Thesis
Recommended Citation
Genil, Francis Gerard d M, "Cytogenetics and isozyme polymorphism of the rice black bug, Scotinophara sp. (Coarctata group) (Hemiptera: Pentatomidae), sampled from the rice fields at the Bicol region" (2007). Undergraduate Theses. 11107.
https://www.ukdr.uplb.edu.ph/etd-undergrad/11107
Document Type
Thesis
