Induction and evaluation of triploidy in Crassostrea madrasensis (Preston)(TH 135)

Mallia, Jyothi V (2004) Induction and evaluation of triploidy in Crassostrea madrasensis (Preston)(TH 135). PhD thesis, Manonmaniam Sundaranar University, Thirunelveli.

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Abstract

The kinetics of extrusion of polarbody is essential to produce triploids. Hence, studies were conducted on polarbody extrusion at 22, 28 and 31(±I)OC. At 31,28 and 23°C, 50% of I polar body was fonned 15, 16 and 18 minutes respectively after fertilization. At 31,28 and 23oC, 50% of II polar body was fonned at 28, 32 and 36 minutes respectively after fertilization. Hence triploid induction treatments were administered 8 minutes after fertilization for producing I meiotic triploids and 17 minutes after fertilization for II meiotic triploids. Among physical methods of induction for triploidy, cold and heat shock treatments were applied. Cold shock at 5°C for 10 minutes duration yielded 42.25% of triploidy. High percentages 42.0 and 41.85 of triploids occurred at 37°C for heat treatment, for 5 and 10 minutes, respectively. In the chemical treatment, among three concentrations of cytochalasin B (0 .05, 0.10 and 0.15 mg/I). 40.0% triploids were obtained in 0.05mg/1 of CB treated fertilized eggs. Another chemical 6-Dimethylarninopurine (6- DMAP) at 50, 100, 150 and 200/lM was tried at various treatment durations of 5,8 and 10 minutes. High percentage of 66.6 triploids was obtained from the fertilized eggs treated in 100/lM concentration of 6-DMAP for 8 minutes. Among the treatments applied for production of meiotic triploids, 6-DMAP (IOO/lM) yielded high percentage (66 .6) of triploids followed by 42.3% by cold (5°C) treatment and 40% in heat (37°C) and CB (0.05mg/l) treated eggs.

Item Type:Thesis (PhD)
Supervisor(s):Muthiah, P
Uncontrolled Keywords:Induction; evaluation of triploidy; Crassostrea madrasensis
Subjects:Fish Biotechnology
Theses
Divisions:CMFRI-Cochin > Marine Biotechnology
ID Code:7251
Deposited By:Dr. V Mohan
Deposited On:01 Feb 2011 16:43
Last Modified:20 Jan 2014 14:34

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