Distributional properties of simpson's index of diversity

Lyons, N. I.; Hutcheson, K.

doi:10.1080/03610927908827782

Cited by 9 publications

(3 citation statements)

References 1 publication

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“…The species diversity the of wood‐colonising fungi was compared for 42‐ and 58‐year‐old vines: Shannon's diversity, H′ (Shannon and Weaver , Magurran ); Simpson's diversity, D (Lyons and Hutcheson ); species evenness, J (Gotelli and Colwell ); species richness (total number of species observed); and relative abundance (proportion of wood fragments per location from which a species was isolated). All calculations were made using Agricolaea in R v.2.14.2 software.…”

Section: Methodsmentioning

confidence: 99%

Various fungal communities colonise the functional wood tissues of old grapevines externally free from grapevine trunk disease symptoms

Bruez

Baumgartner

Bastien

et al. 2016

Australian Journal of Grape and Wine Research

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Background and Aims The objective of this study was to analyse the various fungal communities that colonise functional wood tissues of old vines that did not express symptoms of grapevine trunk diseases (i.e. Esca and Eutypa dieback) in the year of sampling. Plants of the cultivar Baco Blanc a grapevine hybrid of Folle Blanche and Noah used to produce Armagnac in France were sampled. Methods and Results Forty‐two and 58‐year‐old vines, planted in the same vineyard, were uprooted, cut longitudinally and their functional wood tissues sampled. Culture‐dependent and single‐strand conformational polymorphism methods were used to compare the fungal communities colonising these wood tissues. It was shown that the fungal communities were significantly different depending on the age of the grapevines. A total of 421 fungal strains were isolated and identified by internal transcribed spacer region sequencing. Conclusions Many grapevine trunk diseases fungal pathogens, particularly the causal agents of Esca (42‐year‐old vines) and Eutypa dieback (58‐year‐old vines), as well as numerous potentially plant‐beneficial mycoparasites (e.g. Trichoderma spp.), were isolated from the functional wood tissues of old grapevines. Significance of the Study The lack of foliar symptoms among older grapevines may reflect an ‘equilibrium’ among trunk fungal pathogens, mycoparasites and saprobes in the functional wood tissues of trunks.

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Section: Methodsmentioning

confidence: 99%

Various fungal communities colonise the functional wood tissues of old grapevines externally free from grapevine trunk disease symptoms

Bruez

Baumgartner

Bastien

et al. 2016

Australian Journal of Grape and Wine Research

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“…. , m are the relative frequencies, the asymptotic variance of the estimatorĜ n = (m/(m − 1)) 1 − j f 2 j has been derived [22,27]:…”

Section: Heterogeneity: Concept and Measuresmentioning

confidence: 99%

Gini heterogeneity index for detecting uncertainty in ordinal data surveys

Capecchi

Iannario

2016

METRON

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In sample surveys where people are asked to give responses to items by means of ordinal scales it is common to register an inherent indecision generated by both objective and subjective causes. Thus, an effective statistical analysis should take this component into account to avoid bias in estimation, interpretation and prediction. In this paper, we show that the heterogeneity index proposed by Gini and its variants are effective measures to detect such an uncertainty. The relationships of Gini heterogeneity index with the parameter of a mixture model are discussed and exploited as a tool for the exploratory selection of covariates. Then, a real case study is considered to check for the effectiveness of these proposals. Some concluding remarks end the paper.

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“…For example, the Simpson index is an appraisal index for community diversity in ecology and is the first statistical index to use probability theory to describe individual similarity ( Simpson, 1949 ). This index evolved into the Gini–Simpson index, which describes the probability of interspecific encounters in ecology ( Lyons and Hutcheson, 1979 ; Caso and Gil, 1988 ). Subsequently, the Gini–Simpson index has been applied widely in other scientific fields and has evolved further into various professional appraisal indices that use similar statistical methods (or equations; McIntosh, 1967 ; Hunter and Gaston, 1988 ; Dillon et al, 1993 ; Gorelick, 2006 ).…”

Section: Introductionmentioning

confidence: 99%

Variety Discrimination Power: An Appraisal Index for Loci Combination Screening Applied to Plant Variety Discrimination

et al. 2021

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Molecular marker technology is used widely in plant variety discrimination, molecular breeding, and other fields. To lower the cost of testing and improve the efficiency of data analysis, molecular marker screening is very important. Screening usually involves two phases: the first to control loci quality and the second to reduce loci quantity. To reduce loci quantity, an appraisal index that is very sensitive to a specific scenario is necessary to select loci combinations. In this study, we focused on loci combination screening for plant variety discrimination. A loci combination appraisal index, variety discrimination power (VDP), is proposed, and three statistical methods, probability-based VDP (P-VDP), comparison-based VDP (C-VDP), and ratio-based VDP (R-VDP), are described and compared. The results using the simulated data showed that VDP was sensitive to statistical populations with convergence toward the same variety, and the total probability of discrimination power (TDP) method was effective only for partial populations. R-VDP was more sensitive to statistical populations with convergence toward various varieties than P-VDP and C-VDP, which both had the same sensitivity; TDP was not sensitive at all. With the real data, R-VDP values for sorghum, wheat, maize and rice data begin to show downward tendency when the number of loci is 20, 7, 100, 100 respectively, while in the case of P-VDP and C-VDP (which have the same results), the number is 6, 4, 9, 19 respectively and in the case of TDP, the number is 6, 4, 4, 11 respectively. For the variety threshold setting, R-VDP values of loci combinations with different numbers of loci responded evenly to different thresholds. C-VDP values responded unevenly to different thresholds, and the extent of the response increased as the number of loci decreased. All the methods gave underestimations when data were missing, with systematic errors for TDP, C-VDP, and R-VDP going from smallest to biggest. We concluded that VDP was a better loci combination appraisal index than TDP for plant variety discrimination and the three VDP methods have different applications. We developed the software called VDPtools, which can calculate the values of TDP, P-VDP, C-VDP, and R-VDP. VDPtools is publicly available at https://github.com/caurwx1/VDPtools.git.

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Distributional properties of simpson's index of diversity

Cited by 9 publications

References 1 publication

Various fungal communities colonise the functional wood tissues of old grapevines externally free from grapevine trunk disease symptoms

Various fungal communities colonise the functional wood tissues of old grapevines externally free from grapevine trunk disease symptoms

Gini heterogeneity index for detecting uncertainty in ordinal data surveys

Variety Discrimination Power: An Appraisal Index for Loci Combination Screening Applied to Plant Variety Discrimination

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