IRRADIATION AND HEAT AFFECT PEACH POLLEN GERMINATION AND FERTILITY

Pollen from the doubled haploid peach [Prunus persica(L.) Batsch] 'Hal l-D' was irradiated with 0, 290, 530, 820, 1000, 5000, or 9000 Gray (G y) of gamma radiation, 113 mu W . cm(-2) of ultraviolet (UV) radiation , or exposed to 100 degrees C for 2 h. In vitro pollen germination per centages were recorded and pollen mas used to pollinate more than 10,0 00 emasculated or male-sterile peach flowers. Although pollen germinat ion in vitro was stimulated by <1000 Gy of gamma irradiation, seed set following pollination was greatly reduced in all treatments. These re sults suggest that ion levels of irradiation are sufficient to render pollen infertile while still maintaining germination capacity. Such re sults may be useful for pollination-induced parthenogenetic egg divisi on for the production of maternally derived haploids and for the produ ction of interspecific hybrids.