Large scale phenotyping and molecular analysis in a germplasm collection of rocket salad (Eruca vesicaria) reveal a differentiation of the gene pool by geographical origin

Abstract

Cultivated rocket (Eruca vesicaria) is a leafy vegetable highly appreciated for its health-promoting virtues and consumed both raw and cooked as ready-to-use vegetable. Despite Eruca being cultivated worldwide, only a few cultivars are available and limited breeding activities have been carried out so far. Therefore, the genetic resources available represent an unexploited potential source of variation for breeding. In the present study, 155 E. vesicaria accessions from 30 countries across Europe, Asia, Africa, and America have been characterized for 54 qualitative and quantitative morphological and quality traits. Conventional descriptors and automated tools for the determination of the quality, morphology, and colour of leaves have been used. Genetic diversity was assessed using 15 inter simple sequence repeat (ISSR) and simple sequence repeat (SSR) markers. A high level of diversity was evidenced in the collection. Significant differences were found in most of the traits with the exception of five pseudo-qualitative descriptors. The first and second dimensions of a principal component analysis (PCA) with phenotypic traits accounted for 25.69 % of total variation showing a stratification of the genotypes according to the European and Asian origins. In total, 75% of the variation was contained in the first 15 components having eigenvalues higher than 1.0. Also, the population structure divided the collection into two main clusters separating European genotypes from the rest. Furthermore, hierarchical cluster analysis confirmed a geographical separation, grouping the accessions into three major clusters, which were differentiated by plant architecture, leaf and flower colour, leaf water status, leaf blade shape and hairiness of the leaves and stem. Our approach has broadened the knowledge of the diversity within the Eruca gene pool, thus contributing to identify sources of variation and to select the best candidates for cultivated rocket breeding programs, as well as to determine the genetic basis of plant and leaf traits in future genome-wide association studies.

Volatile Profile of Wall Rocket Baby-Leaves (Diplotaxis erucoides) Grown under Greenhouse: Main Compounds and Genotype Diversity

“…(salad rocket) and Diplotaxis tenuifolia (L.) DC. (wild rocket) have been established as crops of economic importance [1,2]. However, germplasm related to these species can be also considered of interest as potential crops [3], as it is the particular case of the edible wall rocket (Diplotaxis erucoides (L.) DC.…”

Plant Genetic Resources for Food and Agriculture: The Role and Contribution of CREA (Italy) within the National Program RGV-FAO

“…In rocket salad, the activities have been mostly addressed to the deep characterization of germplasm providing new evidence on the metabolic profile diversity that distinguish the cultivated from the wild gene pool [164]. Additionally, a core collection of 155 cultivated rocked salad accessions have been established and deeply assessed for 54 morphoagronomic and quality-related traits [165]. The collection enriches the germplasm available at CREA for future GWAS studies and breeding activities.…”

Accelerating Tomato Breeding by Exploiting Genomic Selection Approaches

“…To date, phenotyping is labor and time-intensive and is also largely affected by human errors and biases. For these reasons, robotic devices and aerial vehicles are becoming a big opportunity to increase the accuracy of the phenotypic estimations, which in turn can be used in statistical models [ 48 , 49 , 50 , 51 , 52 ]. The development of statistical models capable of accurately predict marker effects has led to the breakthrough of GS increasing the rate of genetic gain per unit of time.…”