Patterns of variation in Poa annua populations as revealed by canonical discriminant analysis of life history traits

Infestation of southern golf courses with weedy annual bluegrass can be a serious problem and chemical control is less than fully effective. Researchers have classified Poa annua L. into an annual var. annua and a perennial var. reptans. Field and laboratory studies were conducted to evaluate eight P. annua ecotypes: 'Augusta 4', 'Augusta 81, 'Augusta 14', 'Augusta 17', 'Auburn', 'Birmingham, 'Columbia', and 'Purchased', the latter established from seed grown in Oregon. Observations were taken on seedling and reproductive traits, regrowth potential of clones in early summer, and germination of freshly harvested seed to evaluate variability among the selected ecotypes. Only the Birmingham ecotype represented var. reptans, whereas the other seven represented var. annua. The Birmingham population had smaller flag leaves than the Augusta populations (21 vs. 26 mm), fewer panicles at the end of the study (46 vs. 128 particles plant(-1)), and a higher germination percentage of freshly harvested seed (50 vs. 22%). The Birmingham population was the only one of the eight studied which had significant regrowth of clones harvested after completion of the annual life cycle in early June. Canonical discriminant analysis revealed that the cluster of Augusta ecotypes was fairly homogeneous and quite similar to the Purchased check population. The Auburn, Birmingham, and Columbia populations were quite distinct from one another as well as the Augusta-Purchased group. The similarity between the Augusta populations and the Purchased check suggests that the Augusta populations may have been established originally from a similar source of Oregon-grown material; however, similar turfgrass management practices could account for apparent similarities between the Augusta and Purchased populations.