Abstract:Gynogenic haploids through unfertilized ovules and ovaries have been reported from 21 species in 9 families since 1976. This review includes the following subjects: induction frequency of haploids depend on genotypes, developmental stage of explants, temperature pretreatment of the explants, medium composition and the conditions of cultivation. Embryological studies reveal that megaspore and such cells as egg, synergid and antipodals in mature embryo sac initiate the division of forming haploid plants through embryogenesis or callus formation．This technique provides an optimal approach to haploid breeding．
