Principal component and morphological diversity analysis of Job’s-tears ( Coix lacryma-jobi   L.)

The diversity analysis of Job’s-tears (Coix lacryma-jobi L.), an ideal healthy food crop, is a prerequisite in breeding programs and germplasm utilization. The aim of this study was to characterize the phenotypic traits of 94 Job’s-tears accessions (40 cultivated and 54 wild) collected from different geographic areas in China. Principal component (PC) and genetic diversity analyses were conducted on 12 morphological characters: stem node number, panicle branch number, primer branch nodes, panicles per plant, grain number per plant, plant height, 100-seed weight, total bract surface characteristics, total bract texture, total bract shape, total bract color, and pericarp color. The results showed a high variation among the studied materials. The relationship among traits indicated that some traits could be used for indirect selection to evaluate accessions. Based on PC analysis, the first seven PCs in the experiment can summarize the vast majority of the information about the agronomic traits of the 94 Job’s-tears accessions. The accumulative contribution rate accounted for 87.31% of the total variation. Cluster analysis grouped all the accessions into seven clusters, and this revealed that genetic variation was based on variety types, geographic distribution, and morphological characteristics.

Keywords
Genetic diversity; Job’s-tears; morphological traits; principle component analysis.