scholarly journals Classification of Kentucky Bluegrass Genotypes Grown as Spaced-plants

HortScience ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 910-913 ◽  
Author(s):  
Stacy A. Bonos ◽  
William A. Meyer ◽  
James A. Murphy
Keyword(s):  
Growth Habit ◽  
Poa Pratensis ◽  
Flag Leaf ◽  
Principal Component ◽  
Kentucky Bluegrass ◽  
Leaf Length ◽  
Compact Type ◽  
Plant Nursery ◽  
The Common

The apomictic breeding behavior of Poa pratensis L. provides an opportunity to study many unique genotypes that can vary dramatically in characteristics such as disease resistance, stress tolerance and growth habit. The classification of Kentucky bluegrass into types is based on common growth and stress performance characteristics gathered from field turf trials. These classification types include the Compact, Bellevue, Mid-Atlantic, BVMG (`Baron, `Victa', `Merit', and `Gnome'), Common, and Aggressive types. A spaced-plant nursery trial was established in May 1996 to quantify morphological and growth characteristics of 45 cultivars and selections representing the major types of Kentucky bluegrass. Plant height, panicle height, flag leaf height and length, subtending leaf length and width, rhizome spread, and longest extending rhizome were measured 10 days after anthesis. Compact type cultivars had a lower, more prostrate growth habit than the Common, Mid-Atlantic, and Bellevue types. Mid-Atlantic type cultivars had a wider rhizome spread than Compact type cultivars. Principal component analysis of morphological measurements made on spaced-plants supports the classification types of the Common, Compact, Bellevue, Mid-Atlantic, and BVMG, but not necessarily the Aggressive type.

scholarly journals Classification and Inheritance of Morphological and Agronomic Characteristics in Kentucky Bluegrass (Poa pratensis L.)

HortScience ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 274-279 ◽  
Author(s):  
Robert R. Shortell ◽  
William A. Meyer ◽  
Stacy A. Bonos
Keyword(s):  
Classification System ◽  
Agronomic Traits ◽  
Poa Pratensis ◽  
Flag Leaf ◽  
Kentucky Bluegrass ◽  
Leaf Length ◽  
Broad Sense Heritability ◽  
Panicle Length ◽  
Flag Leaf Length ◽  
New Cultivars

The apomictic breeding behavior of Kentucky bluegrass (Poa pratensis L.) results in many unique cultivars. A classification system was previously developed to characterize the large number of Kentucky bluegrass cultivars into different types. However, many new cultivars have been released since the last refinement of the classification system. The objectives of this study were to determine differences in morphological and agronomic characteristics among select Kentucky bluegrass cultivars representing the major classification types and to determine broad-sense heritability estimates for important morphological (plant height, panicle length, flag leaf height, and flag leaf length and width) and agronomic (rhizome spread) traits in Kentucky bluegrass. A spaced-plant nursery trial was established in the spring of 2003 at Adelphia, NJ. One hundred seventy-three cultivars and selections were planted in a randomized complete block design with three replications. The morphological and agronomic traits listed were measured on spaced plants. High Density type cultivars (formerly the Aggressive type cultivars) had the most prostrate growth habit with plant heights of 33 and 43 cm in 2004 and 2005, respectively. Mid-Atlantic and Texas × Kentucky bluegrass hybrids had the widest rhizome spread (Mid-Atlantic = 73 and 121 cm; Texas × Kentucky bluegrass hybrids = 72 and 122 cm) in 2004 and 2005, respectively. Broad-sense heritability estimates were high for plant height (H = 0.84), panicle length (H = 0.88), flag leaf height (H = 0.85), and rhizome spread (H = 0.85); moderate for flag leaf length (H = 0.71); and low for flag leaf width (H = 0.11). This study characterizes new cultivars into respective groups and identifies the genetic inheritance of important morphological and agronomic traits in Kentucky bluegrass.

Effect of leaf nitrogen concentration versus CND nutritional balance on shoot density and foliage colour of an established Kentucky bluegrass (Poa pratensis L.) turf

2006 ◽  
Vol 86 (4) ◽  
pp. 1107-1118 ◽  
Author(s):  
Abdo Badra ◽  
Léon-Étienne Parent ◽  
Guy Allard ◽  
Nicolas Tremblay ◽  
Yves Desjardins ◽  
...  
Keyword(s):  
Poa Pratensis ◽  
Block Design ◽  
Nitrogen Concentration ◽  
Principal Component ◽  
Kentucky Bluegrass ◽  
Shoot Density ◽  
Leaf Nitrogen ◽  
N Concentration ◽  
Randomized Block Design ◽  
N Status

A 3-yr field study was conducted in a loam and a sand site to determine the effects of N, P, and K application rates on N status, shoot density and foliage colour of Kentucky bluegrass clippings and to derive critical N values. The experiment was arranged in a completely randomized block design with four replicates and three nutrients, N (0 or 50 to 300 kg ha-1 yr-1), P (0 or 21.8 to 87.3 kg P ha-1 yr-1), and K (0 or 41.7 to 250 kg K ha-1 yr-1), equally broadcast six times per growing season. We examined N concentration values, log-transformed N concentration values, and CND values for compositional nutrient simplexes comprising one (VN1), three (VN3), five (VN5), or 11 (VN11) macro- and micro-nutrients. Critical values for N expressions were obtained from linear relationships with targeted visual shoot density and foliage colour ratings that were closely related to each other (R2 = 0.92). The highest coefficients of determination (0.975 to 0.980) were obtained with VN5 and VN11. The VN5 values were consistent with literature data and across experimental sites, and were the most successful (99% success) in diagnosing N sufficiency in 328 qualified specimens from commercial sod farms. Compared with raw concentrations, the CND transformation reduced from 0.6 to 0.1 the degree of inter-correlation among nutrients in principal component analysis and was amenable to a χ2 distribution of CND indices. Using a critical imbalance index (CNDr2) of 5.6as χ2 value, and a critical CND IN2 index of 1.5 for a 5-nutrient simplex, we diagnosed as imbalanced 179 qualified specimens of which 110 specimens presented excessively high N level among the 328 qualified specimens in commercial stands. The proposed five-nutrient CND norms proved to be effective in diagnosing N status in Kentucky bluegrass clippings across experimental, literature, and survey data sets. Key words: Plant tissue nutrient diagnosis, DRIS, CND, Kentucky bluegrass nitrogen fertilization, turfgrass shoot density, turfgrass foliage colour

INFLUENCE OF MOWING ON LEAF AND TILLER ORIENTATION OF TURFGRASSES

1982 ◽  
Vol 62 (4) ◽  
pp. 979-982 ◽  
Author(s):  
J. L. EGGENS
Keyword(s):  
Competitive Ability ◽  
Growth Habit ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Leaf Angle ◽  
Annual Bluegrass ◽  
Morphological Adaptations ◽  
Athletic Fields ◽  
Grass Weed ◽  
Prostrate Growth

Annual bluegrass (Poa annua L.) is a major grass weed on athletic fields. Since mowing modifies interspecies competitive ability, a program was initiated to determine if any morphological adaptations to mowing occur which might enable Kentucky bluegrass (Poa pratensis L.) to compete more successfully with annual bluegrass. Changes in leaf and tiller orientation of 11 Kentucky bluegrass cultivars and annual bluegrass in response to mowing or not mowing were measured. The mowing treatment consisted of clipping the grasses at 2, 3, 4 or 5 cm. For the 12 grasses there was a significant increase in leaf angle at the 2- and 3-cm mowing height. The increase was not consistent for all grasses and mowing treatments. Leaf angle was not related to the ability of the cultivars to compete with annual bluegrass. The grasses became more prostrate when mowed. While Kentucky bluegrass cultivars with the most prostrate growth habit have been shown to be more competitive with annual bluegrass, growth habit does not appear to be sufficiently important to be the main criterion for choosing Kentucky bluegrass cultivars for use in regularly irrigated, close clipped athletic fields.

scholarly journals Morphological Characterization of Turf-type Tall Fescue Genotypes

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 615-619 ◽  
Author(s):  
Eric Watkins ◽  
William A. Meyer
Keyword(s):  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Disease Incidence ◽  
Flag Leaf ◽  
Principal Component ◽  
Leaf Width ◽  
Brown Patch ◽  
Plant Nursery ◽  
Turfgrass Quality ◽  
Patch Disease

Recently, turfgrass breeders have developed many improved turf-type tall fescue (Festuca arundinacea Schreb.) cultivars. Due to the large number of cultivars currently available to turfgrass managers and researchers, we have classified turf-type tall fescue cultivars into six groups based primarily on several morphological measurements. This type of classification is important for turfgrass breeders because many breeding decisions are made based on observations in a spaced-plant nursery. The major objective of this study was to classify tall fescue cultivars and selections based on spaced-plant measurements and to then compare those results with turf performance. A spaced-plant nursery consisting of 36 cultivars and selections was established in September 1998 at Adelphia, N.J. Plant height, panicle length, flag leaf width and length, subtending leaf width and length, and subtending internode length were measured 10 days after anthesis in 1999 and 2000. Additionally, a turf trial was established at North Brunswick, N.J., that included the same 36 cultivars and selections. The turf plots were evaluated for several traits including overall turfgrass quality, density, and susceptibility to brown patch disease. Based on principal component analysis of morphological measurements, along with turf trial data, all cultivars and selections were assigned to one of six groups: forage, early-standard, standard, early semi-dwarf, semi-dwarf, and dwarf. In turf plots, the semi-dwarf, early-semi dwarf, and dwarf groups were the top-performing types in terms of overall turfgrass quality, and the forage and early-standard cultivars had the lowest overall quality ratings. The dwarf types did not perform well under summer stress, especially in terms of brown patch disease incidence. The results of this study suggest that when developing cultivars for higher maintenance situations, turf-type tall fescue breeders should focus on the development of semi-dwarf cultivars.

scholarly journals Phenotypic Characterization of Jhum Rice (Oryza sativa L.) Landraces Collected from Rangamati District in Bangladesh

2018 ◽  
Vol 21 (1) ◽  
pp. 47-57
Author(s):  
MZ Islam ◽  
M Khalequzzaman ◽  
MA Siddique ◽  
N Akter ◽  
MS Ahmed ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Oryza Sativa L ◽  
Flag Leaf ◽  
Principal Component ◽  
Morphological Characters ◽  
Leaf Length ◽  
Phenotypic Characterization ◽  
Area Index ◽  
Rice Landraces ◽  
Flag Leaf Length

Genetic diversity of 30 Jhum rice landraces was studied under irrigated condition through Mahalanobis D2 statistic for agro-morphological characters. The landraces were grouped into five clusters. The intercluster distances were higher than intra-cluster distances indicating wider genetic diversity among the landraces of different clusters. The intra-cluster distances were lower in all the cases reflecting homogeneity of the genotypes within the clusters. The principal component analysis exposed that the first five components with vector values > 1 contributed 81.14% of the total variations. The highest number (8) of landraces was observed in cluster IV and the lowest (4) in cluster II. The intra-cluster distance was maximum in cluster III (1.62) containing six landraces and minimum in cluster I (0.57) having six landraces. The highest inter cluster value was 23.44 (between cluster II and V) and the lowest was 7.29 (between cluster III and IV). The highest flag leaf length, leaf area index, filled grains per panicle were found in cluster V while the lowest culm diameter, short duration, low yielding genotypes were clubbed into cluster II. Dwarf stature and lower flag leaf length were recorded into cluster I whereas the highest plant height and panicle length were obtained from cluster IV. Based on canonical vector analysis, culm diameter, days to flowering, days to maturity and length-breadth ratio had maximum contribution towards genetic divergence. Selection of parents from the clusters II and V followed by hybridization would possibly result in desirable transgressive segregants. Finally, Jhum rice landraces need to be conserved in Genebank for future breeding programmeBangladesh Rice j. 2017, 21(1): 47-57

Classification of Observations through Combination of the Dimension Reduction and the Cluster Analysis

2017 ◽  
Vol 7 (8) ◽  
pp. 30
Author(s):  
Hyeuk Kim
Keyword(s):  
Machine Learning ◽  
Principal Component Analysis ◽  
Cluster Analysis ◽  
Unsupervised Learning ◽  
Principal Component ◽  
Component Analysis ◽  
Baseball Players ◽  
Partitioning Around Medoids ◽  
Different Characteristics

Unsupervised learning in machine learning divides data into several groups. The observations in the same group have similar characteristics and the observations in the different groups have the different characteristics. In the paper, we classify data by partitioning around medoids which have some advantages over the k-means clustering. We apply it to baseball players in Korea Baseball League. We also apply the principal component analysis to data and draw the graph using two components for axis. We interpret the meaning of the clustering graphically through the procedure. The combination of the partitioning around medoids and the principal component analysis can be used to any other data and the approach makes us to figure out the characteristics easily.

Philosophcal review of h. white̕s tropological theory in the context of the new philosophy of history

2020 ◽  
Vol 3 (152) ◽  
pp. 92-99
Author(s):  
S. M. Geiko ◽  
◽  
O. D. Lauta
Keyword(s):  
Modern Science ◽  
Historical Knowledge ◽  
Text Organization ◽  
The Social ◽  
History Of ◽  
Actual Material ◽  
The Common ◽  
Historical Nature ◽  
Selection Of

The article provides a philosophical analysis of the tropological theory of the history of H. White. The researcher claims that history is a specific kind of literature, and the historical works is the connection of a certain set of research and narrative operations. The first type of operation answers the question of why the event happened this way and not the other. The second operation is the social description, the narrative of events, the intellectual act of organizing the actual material. According to H. White, this is where the set of ideas and preferences of the researcher begin to work, mainly of a literary and historical nature. Explanations are the main mechanism that becomes the common thread of the narrative. The are implemented through using plot (romantic, satire, comic and tragic) and trope systems – the main stylistic forms of text organization (metaphor, metonymy, synecdoche, irony). The latter decisively influenced for result of the work historians. Historiographical style follows the tropological model, the selection of which is determined by the historian’s individual language practice. When the choice is made, the imagination is ready to create a narrative. Therefore, the historical understanding, according to H. White, can only be tropological. H. White proposes a new methodology for historical research. During the discourse, adequate speech is created to analyze historical phenomena, which the philosopher defines as prefigurative tropological movement. This is how history is revealed through the art of anthropology. Thus, H. White’s tropical history theory offers modern science f meaningful and metatheoretically significant. The structure of concepts on which the classification of historiographical styles can be based and the predictive function of philosophy regarding historical knowledge can be refined.

Study on floral traits and seed setting in parental lines of hybrid rice during early ahu and kharif seasons

2018 ◽  
Vol 78 (3) ◽  
Author(s):  
Aradhana Phukan ◽  
P. K. Barua ◽  
D. Sarma ◽  
S. D. Deka
Keyword(s):  
Seed Set ◽  
Flag Leaf ◽  
Pollen Dispersal ◽  
Pollen Sterility ◽  
Leaf Length ◽  
Floral Traits ◽  
Opening Angle ◽  
Leaf Angle ◽  
Seed Setting ◽  
Parental Lines

Two CMS lines, IR 58025A and IR 68888A along with their maintainers and two fertility restorers, LuitR and IR 36R, were evaluated for flower and plant characters during early ahu (February-June) and kharif (July-November) seasons. IR 58025A showed longer stigmata and styles, and higher spikelet Length/Breadth (L/B) ratio while IR 68888A showed broader stigmata and wider glume opening angle in both the seasons. IR 68888A also exhibited higher pollen sterility during early ahu. IR 36R was characterized with broad anthers. LuitR showed longer and broader anthers with more pollen than others. Plant height, flag leaf length, flag leaf width and area were higher in IR 36R. Panicle exsertion was complete in pollen parents whereas it was 78-80% in CMS lines. The widest flag leaf angle was found in IR 58025B during early Ahu and in IR 36R during kharif. Kharif season was more favourable for growth of the plants with higher seed set percentage while floral traits of the CMS lines were better expressed in early Ahu. Manipulation of the seeding sequence of the parental lines in early Ahu is warranted for better seed set provided the seed crop escapes heavy premonsoon showers during reproductive stage. IR 68888A/LuitR was a good combination for pollen dispersal and seed setting.

Chemometric Analysis for the Classification of some Groups of Drugs with Divergent Pharmacological Activity on the Basis of some Chromatographic and Molecular Modeling Parameters

2018 ◽  
Vol 21 (2) ◽  
pp. 125-137
Author(s):  
Jolanta Stasiak ◽  
Marcin Koba ◽  
Marcin Gackowski ◽  
Tomasz Baczek
Keyword(s):  
Correlation Analysis ◽  
Pharmacological Activity ◽  
Correlation Coefficients ◽  
Principal Component ◽  
Cardiovascular Drugs ◽  
New Drugs ◽  
Analgesic Drugs ◽  
Starting Point ◽  
Chromatographic Parameters

Aim and Objective: In this study, chemometric methods as correlation analysis, cluster analysis (CA), principal component analysis (PCA), and factor analysis (FA) have been used to reduce the number of chromatographic parameters (logk/logkw) and various (e.g., 0D, 1D, 2D, 3D) structural descriptors for three different groups of drugs, such as 12 analgesic drugs, 11 cardiovascular drugs and 36 “other” compounds and especially to choose the most important data of them. Material and Methods: All chemometric analyses have been carried out, graphically presented and also discussed for each group of drugs. At first, compounds’ structural and chromatographic parameters were correlated. The best results of correlation analysis were as follows: correlation coefficients like R = 0.93, R = 0.88, R = 0.91 for cardiac medications, analgesic drugs, and 36 “other” compounds, respectively. Next, part of molecular and HPLC experimental data from each group of drugs were submitted to FA/PCA and CA techniques. Results: Almost all results obtained by FA or PCA, and total data variance, from all analyzed parameters (experimental and calculated) were explained by first two/three factors: 84.28%, 76.38 %, 69.71% for cardiovascular drugs, for analgesic drugs and for 36 “other” compounds, respectively. Compounds clustering by CA method had similar characteristic as those obtained by FA/PCA. In our paper, statistical classification of mentioned drugs performed has been widely characterized and discussed in case of their molecular structure and pharmacological activity. Conclusion: Proposed QSAR strategy of reduced number of parameters could be useful starting point for further statistical analysis as well as support for designing new drugs and predicting their possible activity.

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