| Currently, triticale microspores require a 20 to 28 day humid cold pretreatment to initiate the switch from gametophytic to sporophytic development. The objective of this thesis work was to decrease the time required to pretreat triticale microspores. The study was conducted on three dates and repeated three times within each date. A comparison of nine treatments consisting of three temperatures regimes and three liquid mediums to determine which technique could equal or increase microspore derived embryo (MDE) yields of the cold pretreatment. Donor plants were grown in a growth chamber set at 15/10°C day/night temperatures, 16.5-hour photoperiod and a light intensity of 350-400 mumol m-2 s-1. Microspores were placed on solid induction media at 25°C for 21-28 days. Embryos were transferred to a modified MS media, inserted in an environment set at 22°C with an 8-hour photoperiod and light intensity of 120-180 mumol m-2 s-1. Genotype dependence was evident. There was a consistent replicable MDE yield for AC Ultima, but other cultivar yields were neither consistent nor replicable. The traditional humid cold pretreatment provided greater MDE yields and green plant regeneration than all other pretreatments tested. |
