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.



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
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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