Factors Affecting the Frequencies of Embryo Formation and Haploid Plant Regeneration in Crosses of Hexaploid Wheat with Pearl Millet

Factors affecting the frequency of haploid production from the crosses of hexaploid wheat variety Chinese Spring and pearl millet line NEC-7006 were investigated. Wheat florets were pollinated with pearl millet at their developmental stages ranging from one day before anthesis to one day after anthesis. The embryos obtained were incubated on the culture medium with different combinations of hormones (indole-3-acetic acid and 6-benzylaminopurine) and solidifying agents (Gelrite or agar). The effects of developmental stages of immature embryos at the time of embryo rescue were also investigated in relation to plant regeneration. High frequency (25.4 % ) of embryo formation was obtained by the pollination earlier than the day of anthesis. Plant regeneration of the embryos was despressed on the culture medium supplemented with hormones. The lowest frequency of plant regeneration was found in the culture medium with combination of hormones and Gelrite. On the agarsolidified culture medium without hormones, immature embryos that were 0.7 mm long at 14 days after pollination regenerated into plants at a frequency of 54.4 olo .