Divergent selection for flowering in annual bluegrass and its impact on plant development and turfgrass utility

Annual bluegrass (Poa annua L.) is a widely occurring turfgrass component. Recent efforts to develop cultivars of this species have led to increased interest in selection methods. The objectives of this study were to evaluate the utility of controlled growth studies for divergent selection for flowering and to evaluate the resultant selections for development and turfgrass quality. Two growth cabinet selection runs (1997 and 1998) were made at a constant 20°C and a 16-h photoperiod at low light levels. Selection was based upon the earliest and latest plants to produce a seedhead on the main stem. In the second selection run, mid-flowering selection was made to characterize the population distribution. Selections were grown out in the greenhouse in 1998 and 1999. Selections made in 1998 were seeded into a field study in August 1999 and maintained as golf green turf. Late selections flowered later than early or mid selections and produced more leaves on the main stem prior to inflorescence appearance. Seedhead ripening showed greater uniformity in late selections. Some late selections produced few seedheads under the greenhouse conditions. Selection for divergent flowering types was successful using the method employed. Turf performance was not related to flowering type, indicating that screening for turf performance will be required after initial selection for plant type.