## 1 Introduction  
Minor crops of the family _Brassicaceae_ are highly appreciated in the cuisine, as they provide particular flavors to dishes like salads, pasta, pizza or meat. This group includes leafy vegetables such as watercress (_Nasturtium officinal_ [PERSON]), turnip greens (_Brassica rapu_ L. subsp. _rapu_) and the rocket crops or arugula. Within the rocket germplasm, only the species _Eruca sativa_ Mill. (salad rocket) and _Diplotaxis tenifolia_ (L.[PERSON]. (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. subsp. _erucoides_) [4]. Wall rocket is an annual plant widespread in Central and Southern Europe, Northern Africa and Western Asia, and also naturalized in the template regions of America [5]. The tender leaves of this wild vegetable have been traditionally appreciated for their characteristic pungent and sulfurous flavor. Thus, in different Mediterranean countries, people would collect them for enriching soups, salads, omelettes and pasta dishes [3, 6, 7]. This popularity, combined with the adaptation of the species to the Mediterranean area, offers an opportunity for wall rocket to be established as a crop [4, 8, 9, 10].  
Despite the traditional interest in wall rocket and its potential to become a crop, the organoleptic information for the species is scarce. [PERSON] et al. [4] reported that the volatile profile of wall rocket was rich in isothicyanates (ITCs), as previously described for rocket crops [11]. ITCs are nitrogen- and sulfur- containing compounds derived from the hydrolysis of their precursors, the glucosinolates (GSLs). Although GSLs can derive in several groups of compounds, ITCs are the main hydrolytic compounds obtained upon pH close to 7 and absence of ferrous ions and specific proteins [12]. In the particular case of wall rocket, allyl ITC has been reported as the main compound in the volatile profile of microgreens and seedlings [4]. This compound has been associated with the sensory descriptors of bitter taste, pungent, sulfutrous, mustard-like, horseradish-like and lachrymose, as compiled by [PERSON] et al. [13]. Consequently, its accumulation in high levels can be considered greatly responsible for the characteristic flavor of wall rocket. Furthermore, allyl ITC has been also investigated for its potential health benefits, mainly as antitumoral agent [14; 15; 16]. Therefore, including vegetables that are source of allyl ITC in our diet may have a positive effect in increasing health status.  
The variability at the species level for allyl ITC and other possible novel ITCs in \(D\). _erucoides_ remains unknown, despite the contribution in the flavor attributes and potential nutritional quality of this vegetable. The evaluation of large germplasm collections is an essential starting point for future selection and breeding programs, as it provides information regarding the variability that could be found in the species. It may also allow identifying some promising accessions for the development of commercial varieties. We previously described the volatile profile of wall rocket in microgreens, seedlings and baby-leaves, based on one accession per phenological stage [4], but the intraspecies variability has not been previously studied. In this context, the present study was aimed at (1) evaluating the diversity of the profile of volatiles in a comprehensive set of wall rocket populations at the baby-leaf stage; (2) evaluating the accumulation of the GSL sinigrin in this set of materials, as it is the precursor of allyl ITC and has been previously reported as the main GSL in the species [8; 17; 18]; and (3) describing the co-occurrence of other minor GSLs. Results of this work will increase the knowledge in the species, and will also provide valuable information for current and future breeding programs, as it is a first insight of the variability in this species.