Dormancy of Kentucky Bluegrass Seed in Relation to the Color of Spikelets and Panicle Branches at Harvest1

Abstract

One of the most important factors affecting germination of Kentucky bluegrass (Poa pratensis L.) seed is maturity at harvest. This study evaluated degrees of seed dormancy in 10 cultivars and selections of Kentucky bluegrass harvested at various stages of change in color of spikelet and panicle branches from green to brown.Significant differences in the degree of dormancy at different stages of change in color of panicle branches existed among the entries. ‘Merion’ exhibited the most prolonged dormancy of seed during this period of change in color. The reduction in dormancy was generally accompanied by changes in color, of the panicle branches in particular, from green to brown. A color index was, therefore, proposed to determine the right time for harvesting Kentucky bluegrass seed to obtain maximum germination.