**1. Introduction**

Garlic (*Allium sativum* L.) is one of the most important bulb vegetables and is mainly used as a spice or flavouring agent for foods. It is used in several types of products such as garlic oil, powder, salt, paste, and flakes.

Garlic has a high nutritive value as a rich source of minerals, carbohydrates, proteins, and vitamins. It also contains numerous bioactive molecules such as organic sulphur-containing (S-compounds) compounds and phenolic compounds [1–3].

The organic S-compounds (present in intact garlic cloves are γ-glutamyl cysteine and cysteine sulfoxides, including deoxyallin and mainly alliin [4]. When garlic is mechanically damaged, the vacuolar enzymes (allinase) convert alliin to allicin. Unstable allicin undergoes non-enzymatic degradation to form a variety of volatile S-compounds—ajoene, vinyl-dithiins, and sulphides as mono-, di-, and tri-sulphides [4]. Numerous studies have reported that the organic S-compounds are responsible for the biological activities revealed in different pathological situations [1,2,5].

Garlic is also characterized by phenolic compounds and the main group consists of phenolic acids (mainly as caffeic acids), followed by flavonoids (mainly as quercetin) [6–8]. A lot of research has been conducted to assess the dietary role of phenolic compounds, their characteristics, metabolic pathways, and biological effects, affirming their capacity to scavenge Reactive Oxygen Species (ROS) and to treat a variety of diseases including heart disease and cancer [2,6].

The Puglia region (South-East Italy) in the centre of the Mediterranean basin has a rich agro-biodiversity, with particular reference to landraces (also known as 'local varieties' and 'farmer's varieties'). Landraces are variable, identifiable populations, usually known by a local name, lacking 'formal' crop improvement, and characterized by a marked adaptation to specific environmental conditions of the area of cultivation [9].

Unfortunately, the regional agro-biodiversity of vegetable crops has been partially lost due to several factors. The modernization and intensification of agriculture have resulted in vast agro-biodiversity loss, since farmers grow modern varieties and hybrids and tend to abandon traditional landraces.

As a result of a regional Project (https://biodiversitapuglia.it//), aimed at collecting and identifying vegetable resources at risk of genetic erosion, the province of Foggia was found to be the richest in landraces among the five provinces of the region [10]. In the *Alliaceae* botanical family the most frequent species found was garlic (*Allium sativum* L.). To stimulate the cultivation of landraces from the farmers ('keepers'), their consumption has to be promoted. To do this, the identification and the highlighting of the chemical properties of the landraces compared with the 'commercial' varieties may represent an added value of the product that could push the preference of consumers.

In this view, the present study describes for the first time the chemical properties of six landraces collected in the province of Foggia, along with their main morpho-biometric traits.

#### **2. Materials and Methods**

#### *2.1. Description of Collecting Sites, Plant Materials, and Sampling*

Six landraces of garlic (*Allium sativum* L.) were directly collected from local growers which had very small farms in marginal areas, in the province of Foggia, in the North of Puglia region (Italy), which lies geographically between 41◦54′44′′N and 41◦02′27′′N in latitude and 14◦55′58′′E and 14◦02′27′′E in longitude. All the interested growers had very small farms in marginal areas and all of them adopted low input agronomic practices such as minimum soil tillage, hand weed control and scarce or no use of irrigation, pesticides or fertilizers.

Details of the collected landraces and the collecting sites are presented in Table 1. Bulbs of 'Spanish white garlic' ('Palmieri Import', Afragola (Na); Origin: Spain), widely available on the European and national market, was used as a reference standard. Pictures of the examined genotypes are shown in Figure S1.

Samples of bulbs (3 ± 0.5 kg per each genotype) were well mixed to obtain three independent replicates, each consisting of 15–40 bulbs. Morphological and biometrical measurements on cloves and bulbs were carried out on fresh material, dealing with 7–15 bulbs for each replicate. Chemical analyses of peeled cloves were performed in triplicate for each replicate, after being freeze-dried (CoolSafe SCANVAC, Labo0Gene, Allerød, Denmark), powdered, packed in hermetic jars and then stored in the dark at −18 ± 1 ◦C until the analyses were carried out.


**Table 1.** List of garlic genotypes and description of collecting areas.

 1 As reported in Piano Paesaggistico Territoriale Regionale—PPTR—www.paesaggiopuglia.it/pptr. 2 As reported inhttps://it.climate-data.org/. 3 As reported inhttp://my.meteonetwork.it/station/.
