Repeatability estimates and minimum number of evaluations for selection of elephant-grass genotypes for herbage production

Rodrigues, Erina Vitório; Daher, Rogério Figueiredo; Gravina, Geraldo de Amaral; Viana, Alexandre Pío; Araújo, Maria do Socorro Bezerra de; Oliveira, Maria Lorraine Fonseca; Vivas, Marcelo; Menezes, Bruna Rafaela da Silva; Pereira, Antônio Vander

doi:10.14393/bj-v36n1a2020-42075

Cited by 6 publications

(11 citation statements)

References 21 publications

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“…High repeatability coefficients are desired, because as the repeatability coefficient is increased, the number of evaluations necessary to predict the real value of an individual is reduced (Rodrigues et al, 2020). In the five methods evaluated, one assessment cycle would be 4).…”

Section: Resultsmentioning

confidence: 99%

“…Using repeatability analysis, it is possible to determine the number of assessments required to predict the genotypic value of an individual along sequenced measurements throughout time (Chaves et al, 2018), obtaining predefined coefficients of determination (Cruz et al, 2014). These coefficients allow the reduction of the trial period, costs, and labor, optimizing the process for launching new cultivars (Torres et al, 2015;Rodrigues et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Repeatability and divergence among genotypes of Desmanthus sp. in a semiarid region

Cunha

Santos

Medeiros

et al. 2021

Pesq. agropec. bras.

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The objective of this work was to evaluate the divergence among genotypes of Desmanthus sp. regarding morphological, productive, and qualitative characteristics, as well as to estimate the number of observations necessary to predict the real value of these characteristics. The experiment was conducted in the semiarid of the state of Pernambuco, Brazil, using 26 genotypes of Desmanthus sp. from different locations in the region. Seven evaluations were carried out from July 2013 to July 2014. Tocher’s grouping method and standardized average Euclidean distance were used. The coefficients of repeatability (r) and determination (R2) were estimated using two models of the analysis of variance, principal components based on the correlation or covariance matrix, and structural analysis based on the correlation matrix. The variables with the greatest weights were stem diameter, leaf area index, and forage yield, with frequencies of 22.05, 17.57, and 14.58%, respectively. Morphological, productive, and qualitative variability was observed among the genotypes of Desmanthus sp. All characteristics presented r and R2 of high magnitude in the methods of analysis. Up to four evaluation cycles are required to predict (R2=95%) the real value of stem diameter, peduncle length, plant height, leaf length and width, number of leaves, and pod length.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Repeatability and divergence among genotypes of Desmanthus sp. in a semiarid region

Cunha

Santos

Medeiros

et al. 2021

Pesq. agropec. bras.

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“…Plant height, LI, LL, LW, NLL, BD, SD and LBR showed high magnitude of r and R 2 (Table 5), indicating reliability in estimating the number of evaluations necessary for predict its real value (Rodrigues et al, 2020). Cunha et al (2021) evaluated genotypes of Desmanthus sp .…”

Section: Discussionmentioning

confidence: 98%

Morphology, accumulation and survival of Desmanthus under different planting densities and harvest heights

Medeiros

Santos

Cunha

et al. 2022

Grass and Forage Science

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The use of legumes is an important strategy for animal feeding, especially during the dry season. The aim was to evaluate the effect of planting densities (40,000; 15,625 and 10,000 plants ha−1) and harvest heights (20 and 40 cm) on the morphology, accumulation and survival of Desmanthus (Desmanthus pernambucanus [L.] Thellung), cultivated in subhumid tropical region, as well as to estimate the repeatability of the evaluated characteristics and the optimal number of measurements. The treatments were randomized in blocks, with subdivided plots and four replicates. Planting densities were evaluated in the plots and the harvest heights in the subplots. Eight harvests were carried out with an interval of 84 days. Morphological and productive characteristics and survival were evaluated. Cultivation under density of 40,000 plants ha−1 produced taller plants, with higher leaf area index (LAI = 0.98), light interception (LI = 49%), individual accumulations (18.8 g DM plant−1) and by area (576.5 kg DM ha−1 harvest−1), although resulting in reduced plant stand (66%). Harvest heights do not affect accumulation and survival. It is possible to reduce the number of measurements for stem diameter, number of leaflets per leaf (R2 = 95%), plant height, canopy diameter, LAI, LI, leaf length and width, number of leaves per branch, branch diameter and LBR (R2 = 90%), optimizing resources for future research. Desmanthus has potential for use in protein banks, being harvested in the rainy season, conserved and supplied in addition to animals, but plant growth is minimal during the dry season under rainfed conditions.

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“…When evaluating p cultivars and ƞ repeated measurements, the repeatability coeffi cient can be estimated through the intra-class correlation obtained from the analysis of variance. This model makes it possible to remove effects of temporary environment that might be confused with the variation within the genotypes, contributing to an underestimation of the repeatability coeffi cient (CRUZ; REGAZZI; CARNEIRO, 2012;RODRIGUES et al, 2020).…”

Section: Methods Of Analysis Of Variance (Anova) With Two Factors Of ...mentioning

confidence: 99%

“…The repeatability coeffi cient can be estimated through different methods, such as, for instance, the method of analysis of variance, the method of principal components, and the method of structural analysis (GUILHEN et al, 2019;RODRIGUES et al, 2020). These methods have been applied in the most diverse cultures (DIEL et al, 2020;FERREIRA et al, 2020;PEDROZO et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Repeatability and the optimal number of measurements for screening of soybean cultivars under water deficit

Duarte¹,

Ferreira²,

Silva³

2022

Revista Ciência Agronômica

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This study aimed at determining the optimal number of replications and measurements necessary for the screening of soybean cultivars subjected to three conditions of water availability during the initial stage of development. Two experiments were carried out in a greenhouse. A randomized block design was used, in a factorial scheme with two factors (cultivar and water availability), six replications, ten cultivars and three conditions of water availability (control condition, in which the sand was moistened with water; stress control in the water potential of -0.2 MPa and stress condition in the water potential of -0.4 MPa). At 20 days after cultivation, measurements were taken, subsequently estimating the repeatability coeffi cient, of the number of necessary measurements and of the determination coeffi cient. The repeatability coeffi cient was estimated by distinct statistical procedures, such as method of analysis of variance, principal components with basis on the matrices of phenotypic variances and covariances; principal components with basis on the matrices of correlation and structural analysis. For the determination of the number of replications, the repeatability coeffi cients ranged from low to high in experiment I, except for the root variables, which presented high values in both experiments. In experiment II, in turn, the magnitudes of the determination coeffi cients were above 90%. For plant height, number of leaves, root length and dry matter of the aerial part, only two replications would be necessary to obtain 80% confi dence. Regarding the number of measurements per parcel, only one plant could be evaluated in each parcel, with 85% confi dence for both experiments. Only two replications and one measurement per parcel are enough for high estimates of repeatability. This way, adequate effi ciency is obtained in the selection of superior materials for tolerance to water defi cit, during the initial stages of soybean development.

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Repeatability estimates and minimum number of evaluations for selection of elephant-grass genotypes for herbage production

Cited by 6 publications

References 21 publications

Repeatability and divergence among genotypes of Desmanthus sp. in a semiarid region

Repeatability and divergence among genotypes of Desmanthus sp. in a semiarid region

Morphology, accumulation and survival of Desmanthus under different planting densities and harvest heights

Repeatability and the optimal number of measurements for screening of soybean cultivars under water deficit

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