High-throughput Characterization of Fruit Phenotypic Diversity among New Mexican Chile Pepper (Capsicum spp.) Using the Tomato Analyzer Software

Ehtisham S. Khokhar; Dennis N. Lozada; Amol N. Nankar; Samuel Hernandez; Danise Coon; Navdeep Kaur; Seyed Shahabeddin Nourbakhsh

doi:10.21273/HORTSCI16815-22

HortScience

Issue Date: 01 Dec 2022

Online ISSN: 2327-9834

IssueJournal

Keywords.
Materials and Methods
Results
Discussion
Conclusions
References

Fig. 1.

Scattergrams displaying distribution of different fruit morphometric parameters measured using the Tomato Analyzer. The external fruit features from the longitudinal section were measured by basic measurements: (A) fruit size, (B) fruit shape index, (C) blockiness, (D) homogeneity, (E) proximal fruit end shape, (F) distal fruit end shape, (G) asymmetry, and (H) internal eccentricity. NM = New Mexican pod type.

Fig. 2.

Representative genotypes for different fruit shapes of the Capsicum diversity panel. NM = New Mexican pod type.

Fig. 3.

Hierarchical cluster analysis–derived dendrogram constructed using 32 morphometric Tomato Analyzer (TA) descriptors showing eight clusters. Conical (CL), bell (BL), round (RD), and elongated (EL) group. Cluster 1 (C1; blue), C2 (red), C3 (dark violet), C4 (deep pink), C5 (orange), C6 (brown), C7 (green), and C8 (black).

Fig. 4.

Variance plot displaying variation explained by each principal component. The red line explains the cumulative variation contributed by 32 principal components and the green line indicates variation contributed by an individual component.

Fig. 5.

Genotype by descriptor ellipse biplot displaying genotypes categorized based on the fruit shape revealed by principal component (PC) analysis. Accessions belonging to bell, conical, elongated, round shapes are shown in red, light blue, pink, and purple, respectively. Traits contributing to principal components PC1 and PC2 are also assigned different gradient colors. Color intensities and lengths of the arrows represents the contribution of the traits to the first two principal components. Dark red color and longer arrows indicate a higher contribution of the response variables. Perimeter (P), area (A), width mid-height (WMH), max width (MH), height mid-width (HMW), maximum height (MH), curved height (CH), fruit shape index external I (FSIE I), fruit shape index external II (FSIE II), curved fruit shape index (CFSI), proximal fruit blockiness (PFB), distal fruit blockiness (DFB), fruit shape triangle (FST), circular (C), rectangular (R), ellipsoid (ED), shoulder height (SH), proximal angle micro (PAMi), proximal angle macro (PAMa), proximal indentation area (PIA), distal angle micro (DAMi), distal angle macro (DAMa), distal indentation area (DEA), ovoid (OV), H. asymmetry.ob (HOB), V. asymmetry (VA), eccentricity (EY), fruit shape index internal (FSII), eccentricity area index (EAI), distal eccentricity (DC), proximal eccentricity (PC), and width widest pos (WWP).

Fig. 6.

Correlation network, constructed using 32 morphometric Tomato Analyzer descriptors, illustrates the relationships between eight fruit diversity traits (basic measurements, fruit shape index, blockiness, homogeneity, proximal fruit end shape, distal fruit end shape, asymmetry, internal eccentricity). The width of each band represents the strength of the correlation. Positive correlations are shown by green color bands whereas negative correlations are displayed by red color bands.