Common bermudagrass has been widely used as a major warmseason turf, forage, and soil stabilization grass in the southern United States. However, codominant marker development, linkage, and quantitative trait loci (QTL) mapping resources are limited in the important taxon. Accordingly, the objectives of this study were to develop simple sequence repeat (SSR) markers, construct a genetic map, and identify genomic regions associated with establishment rate. Five genomic SSR libraries were constructed, sequenced, and used in the development of 1003 validated SSR primer pairs (PPs). A linkage map was constructed using a first-generation selfed population derived from a genotype A12359 (2n = 4x = 36). A total of 249 polymorphic SSR PPs were mapped to 18 linkage groups (LGs). The total length of the map is 1094.7 cM, with an average marker interval of 4.3 cM. Ninety-eight out of 252 mapped loci (39%) were found to be distorted from the Mendelian 1:2:1 segregation ratio. Among the other 154 nondistorted loci, 88 coupling vs. 66 repulsion linkage phases were observed to confirm the allopolyploid origin of the parent. Ground coverage (GCR) phenotypic data in the establishment stage were collected in two replicated field trials. Quantitative trait loci mapping identified five genomic regions significantly related to the trait. The findings of this study provide valuable genetic tools and resources for genomic research, genetic improvement, and breeding new cultivars in the species.

Annual bluegrass (Poa annua L.) is a problematic weed on creeping bentgrass (Agrostis stolonifera L.) putting greens. Annual bluegrass produces extensive seedheads in spring, and plant growth regulators (PGRs) are frequently used to suppress seedhead formation. This study investigated the effects of single and sequential applications of mefluidide, maleic hydrazide, and ethephon alone or in combination with trinexapac‐ethyl (TE), on annual bluegrass seedhead formation. A secondary objective evaluated whether addition of TE enhanced the efficacy of ethephon while improving the safety on creeping bentgrass. Three independent studies were established on golf course greens during a 2‐yr period, with initial PGRs application before annual bluegrass seedhead formation. Regardless of PGR treatment, single or sequential applications in all studies showed no differences in annual bluegrass seedhead suppression. Ethephon‐containing treatments provided the best seedhead suppression with up to 95% reduction. No PGR treatments caused visible phytotoxicity to creeping bentgrass following single applications. Sequential applications of both mefluidide and maleic hydrazide caused significant phytotoxicity to creeping bentgrass for up to 3 wk after initial treatment (WAIT). With the exception of one evaluation date in the third study, tank mixture of TE with ethephon had little effect on annual bluegrass seedhead suppression. Tank‐mixing TE with ethephon marginally enhanced turf quality of creeping bentgrass up to 6% compared to ethephon alone.

The components that define cereal-grain yield potential have not been well defined. The objective of this study was to collect many differing biological measurements from a long-term winter wheat (Triticum aestivum L.) study in an attempt to better define yield potential. Four treatments were sampled that annually received 0, 45, 90, and 135 kg N ha −1 at fixed rates of phosphorus (P) (30 kg ha −1 ) and potassium (K) (37 kg ha −1 ). Mid-season measurements of leaf color, chlorophyll, normalized difference vegetative index (NDVI), plant height, canopy temperature, tiller density, plant density, soil moisture, soil NH 4 -N, NO 3 -N, organic carbon (C), total nitrogen (N), pH, and N mineralization potential were collected. In addition, soil texture and bulk density were determined to characterize each plot. Correlations and multiple linear-regression analyses were used to determine those variables that can predict final winter wheat grain yield. Both the correlation and regression analyses suggested mid-season NDVI, chlorophyll content, plant height, and total N uptake to be good predictors of final winter wheat grain yield. Keywords

This study compares preference shares of stress-tolerant, low-maintenance, and low-cost turfgrass attributes in five states (Florida, Georgia, North Carolina, Oklahoma, and Texas) in the southeastern and midsouthern United States using the discrete choice experiment (DCE) and the best–worst method (BWM). An online survey was conducted and a mixed logit model (MLM) was used to determine the homeowners’ relative preferences for turfgrass attributes. The results of a survey of 1179 household consumers indicate that the most preferred attribute using either of the methods was low maintenance cost in all the states. Although the relative importance (preference share) by the DCE and the BWM for each attribute is statistically different, both methods yield a similar preference ordering for low-maintenance, drought-tolerant, and saline-tolerant turf, but a different ordering for shade-tolerant and low purchase–price turf. This study provides a framework for turfgrass researchers and producers to invest and expand outreach on desirable turfgrass attributes for homeowners.

Bermudagrass ( Cynodon dactylon Pers.) is an important warm-season perennial used extensively for turf, forage, soil conservation and remediation worldwide. However, limited genomic information has hindered the application of molecular tools towards understanding genome evolution and in breeding new cultivars. We genotype a first-generation selfed population derived from the tetraploid (4x = 36) ‘A12359’ using genotyping-by-sequencing. A high-density genetic map of 18 linkage groups (LGs) is constructed with 3,544 markers. Comparative genomic analyses reveal that each of nine homeologous LG pairs of C. dactylon corresponds to one of the first nine chromosomes of Oropetium thomaeum . Two nested paleo-ancestor chromosome fusions (ρ6-ρ9-ρ6, ρ2-ρ10-ρ2) may have resulted in a 12-to-10 chromosome reduction. A segmental dissemination of the paleo-chromosome ρ12 (ρ1-ρ12-ρ1, ρ6-ρ12-ρ6) leads to the 10-to-9 chromosome reduction in C. dactylon genome. The genetic map will assist in an ongoing whole genome sequence assembly and facilitate marker-assisted selection (MAS) in developing new cultivars.