colchicine induced embryogenesis and doubled haploid production in maize (zea mays l.) anther culture

this study involves in vitro androgenesis of zea maysl. via anther culture. combination of two embryoinduction media (imss & ypm) in presence of different colchicine concentrations (0, 100, 200, 250, 300and 400 mg/l ) in the pretreatment medium (iml) andpretreatment duration (0, 3, 6 and 9 days) in twogenotypes (dh5×dh7 and eth-m82) were tested.after colchicine pretreatment, anthers were transferred to the induction media without colchicine toinduce of embryo like structures (elss). the elsswere then transferred to plant regeneration medium(ypnas). it was found that in the genotypedh5×dh7, colchicine at a concentration of 100 mg/lsignificantly induced the number of elss (19.6). thecontrol (without colchicine) and 400 mg/l of colchicineresulted in lower levels of elss (5.8, 5.7, respectively). in this genotype, colchicine pretreatment for 3days produced highest number of elss (16.83) anda large increase in the els yield was observed in theypm medium (14.4). in eth-m82 genotype, 6 days ofpretreatment with 300 mgl-1 with colchicine, producedhighest frequency of elss (25). also, in this genotype,a large increase in els yield was observed in theypm induction medium (22.3). the frequency ofspontaneous chromosome doubling in control groupwas very low for both genotypes (7%), but thesegenotypes were able to produce doubled haploidplantlets from the elss (63% doubled haploid) usinga low concentration of colchicine in the pretreatmentmedium (250 mgl-1 for 6 days). at high concentrationsof colchicine (300 and 400 mg/l), more morphologicaland chromosomal aberrations were observed.