ranki {rYWAASB}R Documentation

The values and ranks of genotypes

Description

[Stable]

ranki() function ranks the genotypes (or entries) based on a new index utilizing the given trait and "WAASB" index to simultaneous select the top-ranked ones. This can be compared with WAASBY index of Olivoto (2019). We suggest users handle the missing data in inputs before considering analyses, due rank codes dose not implement a widespread algorithm to do this task. WAASB(Weighted Average of Absolute Scores), Computes the Weighted Average of Absolute Scores (Olivoto et al., 2019) for quantifying the stability of g genotypes conducted in e environments using linear mixed-effect models.

Usage

ranki(datap)

Arguments

datap

The data set

Details

According to Olivoto et al. (2019a), WAASB(The weighted average of absolute scores) is computed considering all Interaction Principal Component Axis (IPCA) from the Singular Value Decomposition (SVD) of the matrix of genotype-environment interaction (GEI) effects generated by a linear mixed-effect model, as follows:

\[ WAASB_i = \sum_{k = 1}^{p} |IPCA_{ik} \times EP_k|/ \sum_{k = 1}^{p}EP_k\]

where \(WAASB_i\) is the weighted average of absolute scores of the ith genotype; \(IPCA_{ik}\) is the score of the ith genotype in the kth Interaction Principal Component Axis (IPCA); and \(EP_k\) is the explained variance of the kth IPCA for k = 1,2,..,p, considering \(p=min(g-1; e-1)\).

Further, \(WAASBY_i\) is a superiority or simultaneous selection index allowing weighting between mean performance and stability \[ WAASBY_i=\frac{\left({rY}_i\times\theta_Y\right)+ \left({rW}_i\times\theta_s\right)}{\theta_Y+\theta_s} \] , where \(WAASBY_i\) is the superiority index for genotype \(\it{i}\) that weights between mean performance and stability; \(\theta_Y\) and \(\theta_s\) are the weights for mean performance and stability, respectively; \({rY_i}\) and \({rW}_i\) are the rescaled values for mean performance \(\bar{Y_i}\) and stability \(W_i\), respectively of the genotype i. For the details of calculations, rescalling and mathematics notations see (Olivoto et al., 2019).

Finally, \(rYWAASB_i\) index is the sum of the ranks of the trait (\(rY_i\)) and WAASB index (\(rWAASB_i\)) for each individual:

\[ rYWAASB_i = {rY_i} + {rWAASB_i}\]

.

The input format of table of data(NA free), here maize data, should be as follows:

GEN Y WAASB WAASBY
Dracma 262.22 0.81 81.6
DKC6630 284.04 2.20 88.5
NS770 243.48 0.33 71.4
...

Value

Returns a data frame showing numerical rankings

Author(s)

Ali Arminian abeyran@gmail.com

References

Olivoto, T., Lúcio, A., DC, da Silva, J.A.G., Sari, B.G. and Diel, M. 2019. Mean performance and stability in multi-environment trials II: Selection based on multiple traits. Agronomy Journal, 111(6):2961-2969.

Olivoto, T., & Lúcio, A.D.C.2020. metan: An R package for multi‐environment trial analysis. Methods in Ecology and Evolution, 11(6), 783-789.

Kang, M.S. 1988. “A Rank-Sum Method for Selecting High-Yielding, Stable Corn Genotypes.” Cereal Research Communications 16: 113–15.

Examples


data(maize)
ranki(maize)


[Package rYWAASB version 0.2 Index]