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Tall fescue is an important cool-season grass widely used for forage and turf, and its genotypic variation for morphological traits has not been well documented. One hundred and fifteen tall fescue accessions, including 25 commercial cultivars, were divided into five groups based on their origination. The morphological traits, including plant height, spike length, pulvinus distance, spikelet count, branch count per spike, spike count per plant, and spike weight in different accessions were determined under field conditions in 2013 and 2014. There was significant genotypic variation in morphological traits among the 115 tall fescue accessions. Wild accessions exhibited a greater variation in the morphological traits than commercial cultivars. Close correlations were found among plant height, spike length, pulvinus distance, and spikelet count. The results of this suggest plant height, spike length, pulvinus distance, and spikelet count could be used as key morphological traits for evaluating all fescue germplasm effectively. Tall fescue (Festuca arundinacea Schreb.), a cross-pollinated, hexaploid, cool-season perennial grass, has been widely grown as an important forage and turf grass throughout the world (Aiken and Strickland, 2013; Seal, 1983). The grass belongs to the tribe Festuceae, subfamily Festucoideae, and family Poaceae (Seal, 1983). Natural populations are distributed in temperate and cool climates throughout Europe, North–West Africa, North America, and west and central Asia ( Cernoch et al., 2003). Tall fescue not only enhances the natural beauty of the environment and increases the value of residential and commercial property (Bonos et al., 2006; Ha et al., 1992), but also provides numerous benefits to humans including providing feed for millions of beef cattle, horses, sheep, and countless wild animals (Wang et al., 2001). Therefore, tall fescue played an important role in pastoral industry, ecological landscaping, soil conservation, and athletic industry (Wang and Xie, 2007). The genetic variability for morphological traits is the key component of breeding programs for broadening the gene pool (ChtourouGhorbel et al., 2011). Variety fescue is the cosmopolitan and ubiquitous taxon, and provides the most important and diverse genetic resources in the species as forage and turf. These variations might be attributed to difference in the genetic constitutions of the population or in the environment where they grow (Dutta et al., 2013). Chtourou-Ghorbel et al. (2011) reported that substantial variation in morphological characteristics among tall fescue cultivars was currently being lost due to severe genetic erosion associated with overgrazing, irregular rainfall, and the loss of rangeland in Tunisia. Majidi et al. (2009) indicated that morphological variation in tall fescue germplasm was heritable, and that several traits including plant height and dry matter yield had a high narrow sense heritability value. Morphological traits are of great importance in selecting rational parents for hybridization breeding of many crops. The knowledge of genotypic diversity was indispensable for efficient utilization of genetic resources and breeding (Beyene et al., 2006; Finger et al., 2010). Plant height, spike length, spikelet count, spike count per plant, and spike weight are major components of plant yield as selection criteria in breeding (Topal et al., 2004). Ebrahimiyan et al. (2012) reported significant genotypic variation in plant height, flag-leaf length, and flag-leaf width among the seventy five tall fescues. The variation of morphological traits was influenced by genotype and environment (Chtourou-Ghorbel et al., 2011). Niazkhani et al. (2014) observed that the plant height had lower direct and positive effect on dry forage yield (correlation coefficient equals to 0.051). Knowledge of relationship among the morphological traits was the basic and most important for plant selection in a breeding program (Hasan et al., 2013). Leaf roughness, poor regeneration ability, and poor stress resistance limit wide utilization of tall fescue (Carrow, 1996; Cross et al., 2013; Xu et al., 2006). Excellent tall fescue cultivars are not only able to produce more biomass, but also survive stress conditions. Fortunately, there was tongs of tall fescue germplasm composed of landraces, commercial cultivars, and breeding lines (Li et al., 2010). Thus, improvement of tall fescue might encourage its use as a forage grass species (Easton et al., 1994). However, genetic variation in morphological traits of tall fescue has not been understood very well. Describing the morphological traits of a large tall fescue collection is still costly and time-consuming. Selecting and describing numerous traits within smaller sample was reasonable and possible. The objectives of this study were to investigate the phenotypic variation of the morphological characteristics and to determine the correlation between the morphological traits. The findings of this study would add new information for better understanding the genetic diversity of tall fescue and therefore facilitate breeding design. Materials and Methods Plant materials and growth conditions. The present research was conducted at Wuhan Botanical Garden, Chinese Academy of Science,Wuhan, China from 2012 to 2014. The climate in this region is of a northern subtropical type, with a warm, humid summer, and an obvious altitudinal change. Maximum, minimum, and mean annual temperature was 29.3 C in July andAugust, 0.4 C in January, and 17.5 C respectively. The Received for publication 3 Dec. 2014. Accepted for publication 23 Jan. 2015. We thank the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) for providing tall fescue germplasm. This work was financially supported by Key laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences (Grant No. Y052811t04). To whom reprint requests should be addressed; e-mail huxu0309@aliyun.com or e-mail xuzhang@ vt.edu. 512 HORTSCIENCE VOL. 50(4) APRIL 2015 mean annual precipitation was 1347.7 mm. The mean annual sunshine duration was 1450–2050 h. The tall fescue accessions used in this study consisted of landraces and commercial cultivars. The distribution and origin of the 115 tall fescue accessions, including 25 commercial cultivars, were listed in Figure 1 and Table 1. The accessions were divided into five groups based on origination (i.e., Cultivar, America, Europe, Africa, and Asia). A single seed from each accession was initially placed on a layer of filter paper which soakedwater in petri dishes inMay, 2012. The petri dishes were placed in the dark at 20 C until germination, and then transferred to 300–500 mmol photons per m·s natural sunlight for 14 h photoperiod. After 2 weeks, all accessions were transferred to plastic containers (15 cm deep and 14 cm diameter) filled with a mixture of cultivation medium and sand (1:1, v/v). Each accessionwas cloned multiple times by tillers to maintain genetic uniformity. All accessions were established in a walk-in growth room with daily maximum and minimum temperature of 24 and 20 C, with a 14-h photoperiod and light intensity of 300 mmol photons per m·s, respectively. They were watered daily to maintain well watered conditions, and fertilized weekly with one-half strengthHoagland’s solution (Hoagland and Arnon, 1950). The grasses were mowed weekly to 7 cm canopy height. In Sep. 2012, the experimental plots were fertilized with 49 kg N/ha, 98 kg P/ha, and 98 kg K/ha. Peat soil (2-cm thick) was applied, and then the soil was subjected to deep-tillage (25–30 cm), raked for smoothness, and then covered with sand (2-cm deep). The 115 accessions were transplanted to the experimental field in a 1.5 · 1.5 m-lattice in Oct. 2012. The fertilizer with the ratio of N:P:K at 21:6:13 was applied in Mar. 2013 to provide 49 kg N/ha. The tall fescue was fertilized monthly from April through November in 2013 with 49 kg N/ha compound fertilizer and urea. After the data were collected in 13 June 2013, the grasses were mowed to the height of 10 cm, and no mowing was conducted at other times during the whole experimental stage. In 2014, the tall fescue was fertilized at 49 kg N/ha each time in April and May with compound fertilizer and urea. Data were collected on 28 May and 7 June in 2014. The experimental field was irrigated as needed to prevent from wilt in 2 years. When irrigated, water was applied to wet the entire root zone. The experimental sites were syringed occasionally during sunny, rain-free periods. Measurements. Data were collected on the plant height, spike length, pulvinus distance, spikelet count, branch count per spike, spike count per plant, and spikeweight from4 June to 13 June in 2013 and from 28 May to 7 June in 2014. Plant height was determined as the distance from the ground level to tip of a plant. Seven uniform plants from accession per replicate were measured and the average was used for statistical analysis. Spike length was defined as the distance from the bottom to the tip of spike. Four plants with an average size from each accession per plot were measured and the average was used for analysis. Pulvinus distance was the distance from main spike neck to flag leaf pulvinus. Four plants with an average size from each Table 1. Tall fescue accession and their geographical origin used in this study. Accession count Geographical origin AST-1 Firenza Matador Coyote II Pixie Cultivar SH 3 Rembrandt SR 8650 Tomahawk GT Grand II Tahoe II Lindergh LS-11 3rd Millennium Smirna Justice Millennium Endeavor Stone wall Silverado II ATM Barlexas Wolfpack Davinci Focus PI 574522 PI 531230 PI 203728 PI 508603 PI 596701 America PI 636597 PI 578717 PI 578718 PI 583822 PI 578724 PI 634238 PI 655112 PI 655113 PI 578719 PI 559374 PI 561430 PI 469244 PI 578714 PI 601106 PI 601227 PI 601447 PI 608024 PI 608025 PI 632516 PI 608787 PI 6

Genotypic Variation of Morphological Traits in Tall Fescue (Festuca arundinacea Schreb.) Accessions