Development of Species-Specific SCAR Markers in Bentgrass

tonia solani Kühn) and red thread [caused by Laetisaria fuciformis (McAlpine) Burdsall] (Beard, 1973; Brilman, Bentgrass species (Agrostis spp.) are cool season turfgrasses that 2001a). However, some cultivars of colonial bentgrass are tolerant of continuous, close mowing heights because of their prostrate growth habit. Some bentgrass species are difficult to distinare beginning to show improved resistance to brown guish because of similar morphological characteristics and genetic patch (Brilman, 2001a; Murphy et al., 2000) and dollar compatibility. Specific DNA technology, such as the use of SCAR spot (caused by Sclerotinia homoeocarpa F.T. Bennett), (sequence characterized amplified region) markers, can be used to with variation of disease severity existing among cultidifferentiate between some species of bentgrass. SCAR markers were vars (Meyer and Bonos, 2001; Murphy et al., 2000). created by sequencing a single RAPD (random amplified polymorphic Hybrids of the two bentgrass species show increased DNA) band and designing primers to amplify the band of specific size. disease resistance and better turf quality (Brilman, Two SCAR primer pairs were designed to identify colonial (Agrostis 2001a). With more and more restrictions on fungicide capillaris L.) and creeping (Agrostis palustris Huds.) bentgrass speuse, it is becoming important to improve creeping bentcies. The colonial SCAR primers amplify a band of 400 base pairs grass cultivars resistant to turfgrass diseases. (bp) and are designated Col400F and Col400R. The creeping SCAR primers amplify a band of 700 bp and are designated Creep700F and Because of the complexity of the Agrostis genus, Creep700R. Testing with 17 cultivars (140 plants) representing four creeping and colonial bentgrass species are very difficult bentgrass species, single unique bands were correctly amplified for to classify solely on the basis of their morphological creeping and colonial bentgrass species by their respective SCAR characteristics (Yamamoto and Duich, 1994). Both are primer pair. Differentiating these species by SCAR markers is useful characterized by dense mats, strong stoloniferous growth, for screening large numbers of clones collected from superior patches shallow roots, long narrow leaves, and a light green to of naturalized populations on old golf courses and lawns. These SCAR bluish green appearance (Beard, 1973). Another commarkers also have useful potential for identifying progenies derived plication in identification results from natural interspefrom artificial interspecific hybridizations among bentgrass species, cific hybridization between creeping and colonial bentespecially between colonial and creeping bentgrass. grass and artificial interspecific hybridization forced by breeders (Stuckey and Banfield, 1946; Bradshaw, 1958). Because colonial and creeping bentgrass are genetically B species are cool season turfgrasses native compatible, natural hybridization occurs, creating a vato western Europe. There are over 200 species of riety of clones with mixed traits. Currently, identifibentgrass with five species used commercially in the cation of hybrids relies on morphological characters USA (Hitchcock, 1951). These include creeping bentsuch as various flowering structures. Natural hybrids of grass (A. palustris), colonial bentgrass (A. capillaris, creeping and colonial bentgrass that survive biotic and syn A. tenuis Sibth.), velvet bentgrass (A. canina L.), abiotic stresses can be mistaken for a true colonial or and redtop bentgrass (A. alba L.). Another bentgrass creeping bentgrass species. Thus, clones collected from species called dryland (A. castellana Boiss. and Reuter) old turf could easily be mislabeled. This has already is also used; however, it is often mistakenly grouped occurred in New York where creeping and colonial benwith colonial bentgrass (Brilman, 2001a). Creeping and tgrass hybrids taken from a golf course were mistakenly colonial bentgrass are the two most commonly used labeled as colonial bentgrass because of their growth species. Creeping bentgrass is generally used for golf form (Brilman, 2001b). On the other hand, breeders course putting greens, tees, and closely mowed fairways intentionally hybridize creeping and colonial bentgrass because of its tolerance of low mowing heights and its species to combine important traits, such as brown patch strong stoloniferous growth habit (Beard, 1973). Coloresistance, into a single clone. It is necessary to identify nial bentgrass is used on golf courses, lawns, and in which of these offspring are true hybrids. This is particuerosion control (Beard, 1973; Hitchcock, 1951). Howlarly difficult in creeping and colonial bentgrass hybrids ever, it is often considered inferior to creeping bentgrass where there are no major morphological traits differfor greens and fine turfgrass areas because some varieentiating parents. Therefore, it would be best to use a ties have an unfavorable growth habit (Dudeck and molecular test coupled with morphological characterisDuich, 1967). Colonial bentgrass is known to be susceptics to detect hybrids. tible to diseases such as brown patch (caused by RhizocSeveral molecular methods have been used to distinguish between bentgrass species and cultivars. AcrylElizabeth A. Scheef and Geunhwa Jung, Dep. of Plant Pathology, amide gel disk electrophoresis was used by Wilkinson University of Wisconsin-Madison, Madison, WI 53706; Michael D. and Beard (1972) to distinguish seed and vegetatively Casler, Dep. of Agronomy, University of Wisconsin-Madison, Madipropagated creeping bentgrass varieties. Isozyme elecson, WI 53706; This research was supported by Hatch formula fund Wiso 4406. Received 28 Nov. 2001. *Corresponding author (jung@ Abbreviations: bp, base pairs; RAPD, random amplified polymorphic plantpath.wisc.edu). DNA; RFLP, restriction fragment length polymorphism; SCAR, sequence characterized amplified region. Published in Crop Sci. 43:345–349 (2003).