Pollen release by diploid and tetraploid sugar-beet plants



Pollen released during three summers at Broom's Barn, Suffolk, by diploid and tetraploid multigerm sugar-beet plants was caught by automatic volumetric spore traps and by glass funnels situated in the crop. Tetraploids produced on average 66% as much pollen as diploids, their pollen grains were larger and they needed drier air to release pollen, the concentration of which increased more slowly early in the day and was particularly small on dull, damp days. Pollen catches from diploids and tetraploids decreased at a similar rate with increasing distance from the pollinators. The germination of fruits harvested from male-sterile plants among the pollinators was consistently less with a tetraploid than with a diploid pollinator, but was not affected by distance of the male-sterile plants from either pollinator.