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golf putting green turf in the southern USA through greatly improved playability characteristics as well as Off-type bermudagrasses (Cynodon spp.) continue to be a major much-needed uniformity by way of planting a singleconcern on southern U.S. golf greens because of the disruption of surface source cultivar. Uniformity in these vegetatively propauniformity and playability. The current study was undertaken to measure the genetic stability of six bermudagrass cultivars (Champion, Floradwarf, gated turf cultivars is achieved through single-node se- MS-Supreme, Tifdwarf, TifEagle, and Tifgreen) in response to the two dilection from an individual plant. The genetic base of nitroaniline herbicides pendimethalin {N-(1-ethylpropyl)-3,4-dimethyl-2, each cultivar is thus necessarily quite narrow and the 6-dinitrobenzenamine} and oryzalin (3,5-dinitro-N 4 N 4 -dipropylsufnarrow genetic base of these cultivars may pose a risk fanilamide), which are commonly applied for preemergent weed confor extensive damage from virulent or introduced pests trol in turf management. Four off-types (Off-Type 1, Off-Type 2, Off-(Taliaferro, 1995) Type 3, and Off-Type 4) were derived from Champion treated with Within approximately 10 yr of the release of Tifgreen, dinitroanilines during the experimental cycles. The amplified fragment the first "off-types" of bermudagrass were documented length polymorphism (AFLP) analysis identified a total of 311 inforand one of those became the very popular cultivar Tifmative fragments with seven primer combinations, of which 162 (52.09%) were polymorphic. The number of polymorphisms detected dwarf (Burton, 1966). The perception of the term offper primer combination ranged from 18 to 27. The grouping of cultitype is generally negative and is associated with an undevars according to molecular and morphological data was made by sirable entity that likely differs in growth habit and color multidimensional analyses: cluster analysis and canonical discriminant and disrupts uniformity and playability of the turf. Offanalysis (CDA). Phenetic analysis as well as CDA revealed that all types are particularly difficult to manage on golf putting bermudagrasses and off-types were genetically diverse. Pairwise D 2 greens, where trueness of ball roll is of the utmost imestimates ranged from 0.69 to 0.99 with Off-Type 3 being the most portance. genetically dissimilar. Unweighted pair-group method arithmetic av-It is worth noting that almost all the latest generation erage analysis (UPGMA) produced two major clusters. The first conof bermudagrasses for putting greens, often referred to tained the six bermudagrass cultivars and Off-Type 1, Off-Type 2, and Off-Type 4, while Off-Type 3 formed the second cluster. Total

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Nine sites of cogongrass were included in a study of genotypic diversity and spread dynamics at the point of introduction and its adjacent areas in the southern United States. Clones evaluated with two primer pairs yielded a total of 137 amplified fragment length polymorphism (AFLP) loci of which 102 (74.4%) were polymorphic. Genetic diversity was measured as the percentage of polymorphic, Shannon's information index, Nei's gene diversity, and panmictic heterozygosity. Nei's gene diversity (HS) across all nine sites was estimated to be 0.11 and within site gene diversity ranged from 0.06 to 0.16. Bayesian estimate of gene diversity and Shannon's information index were higher (0.17 and 0.17, respectively). The samples from the point of introduction (Pi) had the lowest genetic diversity for all types of estimates. Within site variance accounted for 56% of the total variation and among site variance 44% (P < 0.05). Differentiation among sites was assessed using F ST. The greatest difference was found between the Pi and the others. No relationship was found between genetic and geographic distances. Principal component analysis as well as cluster analysis separated individuals into three main clusters. The Pi formed a separate subcluster. Gene flow (Nm), inferred from Φ-statistics describing the genetic differentiation between pairs of sites ranged from 0.6 to 5.55. The lack of significant relationship between gene flow and geographic distance as well as genetic and geographic distances suggests that the invasion dynamics of cogongrass into the southern United States is primarily through anthropogenic activities and to the lesser extent through natural forces.

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