Intraplant instability in smooth bromegrass (Bromus inermis leyss)

Intraplant variation in smooth bromegrass was examined by determining pollen stainability and size in 6 moderately self-compatible S-2, and 12 self-incompatible OP-3 plants. Statistically significant differences in pollen stainability occurred between panicles within plants, between plants, and between plants x within plant interactions. Pollen diameter distributions for OP-3 plants tended to be trimodal, and bimodal distributions occurred in S-2 plants. In trimodal distributions, peaks occurred at known diploid and tetraploid chromosome levels, and it is presumed that the peak between these represented the triploid gametic number.Results of cooperative investigations of the Crops Research Division, ARS, USDA, and the Wisconsin Agricultural Experiment Station, Madison. The statistical analyses were made by the Numerical Analysis Laboratory, University of Wisconsin.