CYTOLOGICAL ANALYSIS OF THE POLLEN OF HAPLOIDY INDUCER LINES IN MAIZE (ZEA MAYS L.)

Abstract

Cytological analysis was attempted to study the mechanism of origin of maternal haploids involving Haploidy Inducer Lines (HILs) developed from a high haploid inducer strain 'Stock 6' of maize. The possibility of degeneration or loss of a sperm nucleus in the pollen grain and tubes was studied using flourescent stains in the HILs and compared with that of the control inbreds. Binucleate pollen grains appeared in HILs albeit with frequencies too low to account for anomalies leading to haploid induction. Pollen tubes with two nuclei were observed with high frequency in both the HIL and the control. In such tubes, two gamete nllclei were regularly present and the vegetative nucleus was not visible, thus arguing against any anomaly in the number of male gametes in the HIL pollen tubes. Other anomalies like presence of more than one pollen tube per pollen or branched pollen tubes were also not detected. It is concluded that nuclear anomaly does not occur· in the pollen and tubes of HILs and is, therefore, not the cause of haploidy induction in these lines.