There has been extensive research to document the effects of various turfgrass physiological and morphological characteristics on wear tolerance of currently used varieties. Physiological characteristics associated with improved wear tolerance across a wide range of cool and warm-season turfgrass species include, but are not limited to, total cell wall content (Brosnan et al., 2005; Shearman and Beard, 2002; Trenholm et al., 2000), lignin content (Shearman and Beard, 1975; Trenholm et al., 2000), leaf moisture content (Brosnan et al., 2005; Trenholm et al., 2000), and shoot nutrient levels (Shearman and Beard, 2002; Trenholm et al., 2000). However, assessing these physiological characteristics often requires destructive sampling and various laboratory analyses that are time consuming and expensive.
Morphological characteristics, on the other hand, are often assessed relatively quickly and inexpensively in the field and generally require little or no laboratory analysis. Morphological characteristics that have been associated with improved wear tolerance across a variety of cool and warm-season turf species include internode length (Wood and Law, 1974), density (Shearman and Beard, 1975; Trenholm et al., 2000; Wood and Law, 1974), leaf angle (Wood and Law, 1974), leaf width (Shearman and Beard, 1975), and turf quality (Bonos et al., 2001).
New techniques have been recently developed to objectively quantify various turf canopy morphological characteristics; i.e., turf quality (Bell et al., 2002; Trenholm et al., 1999), color (Karcher and Richardson, 2003), and cover (Goddard et al., 2008; Kowalewski et al., 2013). For example, NDVI and other spectral reflectance parameters have been used to evaluate turf quality (Bell et al., 2002; Trenholm et al., 1999). Richardson et al. (2001) developed digital image analysis techniques to assess percent green turf color and DGCI. In addition to determining turf quality, spectral reflectance and digital image analysis have both been used to successfully quantify turfgrass wear tolerance (Goddard et al., 2008; Haselbauer et al., 2012; Kowalewski et al., 2013; Trappe et al., 2012).
The objectives of this research were to 1) assess the differences in leaf and canopy morphology and wear tolerance of four hybrid bermudagrasses and 2) assess the correlations between these morphological characteristics and wear tolerance. Findings from this research could provide hybrid bermudagrass turf breeders with a list of foliar morphological characteristics that are associated with wear tolerance to select for in new hybrids. Breeders could then use these parameters to identify potentially wear-tolerant experimental crosses before release, rather than wait for additional turf scientists to later conduct field traffic studies. Until recently, it has been more common for wear tolerance to be determined after a variety becomes commercially available, while breeders have selectively concentrated on other characteristics such as decreased mowing height, increased density, improved quality and color, and cold tolerance (Burton, 1966; Hanna et al., 1997).
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