B-III PROGENY (2N-NOTATUM OBTAINED THROUGH EARLY POLLINATION(N) FROM APOMICTIC PASPALUM)

An apomictic tetraploid (2n = 4x = 40) cytotype of Paspalum notatum (B ahiagrass) was emasculated and pollinated from 1 to several days prior to anthesis (DPA). Two pollen sources were used: the tetraploid (4x) cytotype and a diploid (2x) variety (Pensacola Bahiagrass). Spikelets pollinated with pollen of the 4x plant at 1 DPA gave rise to only 4x s eedlings, indicating a 2n + 0 parthenogenetic origin. When pollination was achieved 2 DPA, 46% of recovered seedlings were considered to be B-III progenies produced through fertilization of the unreduced egg ce ll of an aposporous embryo sac with a reduced sperm nucleus (2n + n = 40 + 20 = 60). Few seedlings were recovered from 3 DPA, and all were t etraploid, originated through parthenogenesis (2n + 0). When diploid P ensacola Bahia grass was the pollen donor, all seedlings from 1 DPA we re parthenogenetic tetraploids (2n + 0), whereas most from 2 or 3 DPA were B-III progenies (2n + n) and had 50 chromosomes (2n = 40 + n = 10 ). Control seedlings, from pollinations at anthesis time, were all tet raploid (2n + 0), as expected. These results indicate that time of pol lination may be manipulated in an apomictic species to increase the pr oduction of B-III progenies. Early pollinations, in some cases, preven t parthenogenetic development of the unreduced egg cell in an aposporo us embryo sac, allowing its fertilization.