The apomictic breeding behavior of Kentucky bluegrass (Poa pratensis L.) results in many unique cultivars. A classification system was previously developed to characterize the large number of Kentucky bluegrass cultivars into different types. However, many new cultivars have been released since the last refinement of the classification system. The objectives of this study were to determine differences in morphological and agronomic characteristics among select Kentucky bluegrass cultivars representing the major classification types and to determine broad-sense heritability estimates for important morphological (plant height, panicle length, flag leaf height, and flag leaf length and width) and agronomic (rhizome spread) traits in Kentucky bluegrass. A spaced-plant nursery trial was established in the spring of 2003 at Adelphia, NJ. One hundred seventy-three cultivars and selections were planted in a randomized complete block design with three replications. The morphological and agronomic traits listed were measured on spaced plants. High Density type cultivars (formerly the Aggressive type cultivars) had the most prostrate growth habit with plant heights of 33 and 43 cm in 2004 and 2005, respectively. Mid-Atlantic and Texas × Kentucky bluegrass hybrids had the widest rhizome spread (Mid-Atlantic = 73 and 121 cm; Texas × Kentucky bluegrass hybrids = 72 and 122 cm) in 2004 and 2005, respectively. Broad-sense heritability estimates were high for plant height (H = 0.84), panicle length (H = 0.88), flag leaf height (H = 0.85), and rhizome spread (H = 0.85); moderate for flag leaf length (H = 0.71); and low for flag leaf width (H = 0.11). This study characterizes new cultivars into respective groups and identifies the genetic inheritance of important morphological and agronomic traits in Kentucky bluegrass.
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