02244naa a2200301 a 450000100080000000500110000800800410001910000180006024501770007826000090025552013450026465000180160965000220162765000170164965000320166665000160169865000120171465000120172665000110173865300160174965300140176565300150177965300230179465300120181765300210182965300210185077300710187112786282024-05-21       1989    bl uuuu     u00u1 u    #d1 aRAJORA, O. P.  aPollen competition among Populus deltoides Marsh., P. nigra L. and P. maximowiczii Henry in fertilizing P. deltoides ovules and siring its seed crop.h[electronic resource]  c1989  aInterspecific pollen competition among P. deltoides, P. nigra and P. maximowiczii in fertilizing P. deltoides ovules was studied by using a pollen mixture technique and evaluating isoenzymes and leaf morphology. The frequencies of F1 seedlings of different paternities in pollen-mix crosses showed highly significant departures from the 1 : 1 ratio expected if pollen selection was random. P. deltoides pollen was the most competitive. The mean percentages of F1 seedlings of P. deltoides paternity in crosses with P. deltoides + P. nigra, P. deltoides + P. maximowiczii, and P. deltoides + P. nigra + P. maximowiczii pollen mixtures were 95.0, 92.5 and 84.8%, respectively. P. maximowiczii pollen was more competitive than P. nigra pollen, which was at a selective disadvantage. An average of 83.6% of F1 progenies of the 8 crosses with P. nigra + P. maximowiczii pollen showed P. maximowiczii paternity. Also, in 4 crosses with P. deltoides + P. nigra + P. maximowiczii pollen, the relative proportion of P. deltoides X P. maximowiczii seedlings (13.4%) was higher than that of P. deltoides X P. nigra seedlings (1.8%). Pollen proportions in the pollen mixtures and pollen size did not significantly affect the competitive ability of the pollen. The relative pollen competitive ability indicated reproductive affinities among the species.  abiotechnology  across pollination  aforest trees  ainterspecific hybridization  apollination  aPopulus  aHibrido  aPólen  aBroadleaves  aIsoenzyma  aIsoenzymes  aPollen competition  aPoplars  aSelecao gametica  aSelf pollination  tSexual Plant Reproduction, Heidleberggv. 2, n. 2, p. 90-96, 1989.