Multitrait index based on factor analysis and ideotype‐design: proposal and application on elephant grass breeding for bioenergy

Abstract

This study proposes a new multitrait index based on factor analysis and ideotype-design (FAI-BLUP index), and validates its potential on the selection of elephant grass genotypes for energy cogeneration. Factor analysis was carried out, and afterwards, factorial scores of each ideotype were designed according to the desirable and undesirable factors, and the spatial probability was estimated based on genotype-ideotype distance, enabling genotype ranking. In order to quantify the potential of the FAI-BLUP index, genetic gains were predicted and compared with the Smith-Hazel classical index. The FAI-BLUP index allows ranking the genotypes based on multitrait, free from multicollinearity, and it does not require assigning weights, as in the case of the SmithHazel classical index and its derived indices. Furthermore, the genetic correlation -positive or negative -within each factor was taken into account, preserving their traits relationship, and giving biological meaning to the ideotypes. The FAI-BLUP index indicated the 15 elephant grass with the highest performance for conversion to bioenergy via combustion, and predicted balanced and desirable genetic gains for all traits. In addition, the FAI-BLUP index predicted gains of approximately 62% of direct selection, simultaneously for all traits that are desired to be increased, and approximately 33% for traits which are desired to be decreased. The genotypes selected by the FAI-BLUP index have potential to improve all traits simultaneously, while the Smith-Hazel classical index predicted gains of 66% for traits that are desired to be increased, and À32% for traits that are desired to be decreased, and it does not have potential to improve all traits simultaneously. The FAI-BLUP index provides an undoubtable selection process and can be used in any breeding programme aiming at selection based on multitrait.

Combining Ability of Biomass Sorghum Lines for Agroindustrial Characters and Multitrait Selection of Photosensitive Hybrids for Energy Cogeneration

“…The value of q will be equal to 1 if s 2 s = 0, will by equal to 0.5 if s s s = + 2 2 2 s g1 g2 , and will be <0.5 when s s s > + 2 2 2 s g1 g2 . The FAI-BLUP index was used in the selection of hybrids, according to the R script provided by Rocha et al (2018). All analysis of this work was performed with the use of software R (R Core Team, 2017).…”

Selection indexes based on linear‐bilinear models applied to soybean breeding

“…Thus, the FAI‐BLUP index considers the magnitude and sense of correlation traits. In this way, the relationship between traits is preserved, giving biological meaning to the ideotypes (Rocha et al., ). This index uses the factor analysis concept to analyze the performance of genotypes; predicted genetic values (BLUP) are used and probability is based on the genotype–ideotype design.…”

“…Genetic values (BLUP means) were also submitted to a multitrait index based on factor analysis and genotype-design, known as the FAI-BLUP index. Principal component analysis, factor analysis, and genotype-ideotype were performed using the FAI-BLUP index routine developed by Rocha et al (2018) in R software (R Development Core Team, 2018). For each trait, the ideal values for the ideotype design were defined, considering the minimum, mean, and maximum values of the data set (Table 1).…”

“…Thus, the FAI-BLUP index considers the magnitude and sense of correlation traits. In this way, the relationship between traits is preserved, giving biological meaning to T A B L E 6 Estimates of selection gain (SG) by FAI-BLUP a , GGE, GYT, and GYT-BLUP indexes considering the genotypic values (BLUPs) for grain yield (GY, kg ha -1 ), plant height (PLH, cm), days to maturation (DM, days), first pod insertion (FPI, cm), hectoliter weight (PH, kg hL -1 ), thousand grain weight (TGW, g), oil content (OIL, %), and protein content (PRT, %) the ideotypes (Rocha et al, 2018). This index uses the factor analysis concept to analyze the performance of genotypes; predicted genetic values (BLUP) are used and probability is based on the genotype-ideotype design.…”

“…Based on this method, many adaptations have been proposed to overcome these limitations and select multiple traits. Recently reported selection indexes may be mentioned the Superiority Index (SI) obtained using the Grain Yield × Trait (GYT) approach (Yan & Frégeau-Reid, 2018), which considers genotype and location effects as fixed; and ideotypedesign index (FAI-BLUP) (Rocha, Machado, & Carneiro, 2018), which uses a mixed model approach.…”