Colchicine induced embryogenesis and doubled haploid production in maize (Zea mays L.) anther culture

This study involves in vitro androgenesis of Zea mays L. via anther culture. Combination of two embryo induction media (IMSS & YPm) in presence of different colchicine concentrations (0, 100, 200, 250, 300 and 400 mg/l ) in the pretreatment medium (IML) and pretreatment duration (0, 3, 6 and 9 days) in two genotypes (DH5×DH7 and ETH-M82) were tested. After colchicine pretreatment, anthers were transferred to the induction media without colchicine to induce of embryo like structures (ELSs). The ELSs were then transferred to plant regeneration medium (YPNAS). It was found that in the genotype DH5×DH7, colchicine at a concentration of 100 mg/l significantly induced the number of ELSs (19.6). The control (without colchicine) and 400 mg/l of colchicine resulted in lower levels of ELSs (5.8, 5.7, respectively). In this genotype, colchicine pretreatment for 3 days produced highest number of ELSs (16.83) and a large increase in the ELS yield was observed in the YPm medium (14.4). In ETH-M82 genotype, 6 days of pretreatment with 300 mgl-1 with colchicine, produced highest frequency of ELSs (25). Also, in this genotype, a large increase in ELS yield was observed in the YPm induction medium (22.3). The frequency of spontaneous chromosome doubling in control group was very low for both genotypes (7%), but these genotypes were able to produce doubled haploid plantlets from the ELSs (63% doubled haploid) using a low concentration of colchicine in the pretreatment medium (250 mgl-1 for 6 days). At high concentrations of colchicine (300 and 400 mg/l), more morphological and chromosomal aberrations were observed.