Joyce A. Burns

Effect of microspore stage and media on anther culture of peanut (Arachis hypogaea L.)

This study was designed to study the effects of stage of microspore development and culture medium on androgenic response in peanut (Arachis hypogaea L.). Anthers of various developmental stages were cultured for 7 days, then fixed and observed cytologically. Three sets of media, involving different basal media, growth regulators, sucrose levels and glutamine concentrations, were tested. In all experiments, the stage of development of the microspores at the time of culture was highly significant. The early uninucleate microspores stage was identified as producing the highest anther response rating. The effect of media was nonsignificant in all experiments. However, the stepwise modification of the media through the course of the study resulted in an almost 8 x increase in anther response rating. Numerically, the best media tested was N6 basal medium with 1 mg 1-1 NAA, 0.1 mg 1-1 BA, 5.5% sucrose, and 3.5 g 1-1 glutamine. While no haploids were obtained, four-nucleate cells were observed, indicating the potential in peanuts for an androgenic reponse.

An evaluation of the use of irradiated pollen for gene transfer in Nicotiana

The use of irradiated pollen to effect ‘egg-transformation’ in Nicotiana was tested using a nuclear chlorophyll-deficiency marker. Yellow-green (yg) plants of Nicotiana tabacum were pollinated with pollen from N. glutinosa which had received 50, 75, or 100 krads of gamma-irradiation. Progeny were scored for leaf color and chromosome number. Only one possible transformant was recovered; however, upon selfing, this plant segregated for leaf color. Thus, it could not be determined if this plant was the result of contaminant pollination, mutation, or a transformation event that occurred after diploidization. All other dark green plants had at least one intact chromosome from N. glutinosa. While no evidence in support of the egg-transformation theory was obtained from this study, cytological data concerning the use of irradiated pollen for haploid induction and for the rapid production of alien chromosome addition lines was presented.