A detailed investigation was carried out to study the exact cause and the sequence of events leading to the origin of high frequency of haploids in the high haploidy inducer lines (Stock 6 lines) in maize (Zea mays L). Microtome sections and isolated embryo sacs were observed to understand the fertilization process in maize. These studies helped in understanding the normal fertilization process and also in tracing out a few anomalous fertilization events in these ovules. The study indicated that, haploid embryos in these lines arise due to a failure in the fusion of the sperm nucleus and the egg cell, after the release of sperm nuclei from synergid into the embryo sac, with the egg cell being induced to develop parthenogenetically into a haploid embryo
