Origin of the Barretero variety

To obtain this variety, a selection of plants with good vigor and absence of disease symptoms were carried out in a commercial plot in the town of Chaparrosa in the municipality of Villa de Cos in the state of Zacatecas. The selection plot had previously been established for several cycles with a genotype from Baja California, Mexico.

At the experimental level a mass selection was carried out, eliminating non-type plants during the first evaluation and selection cycle; from the second evaluation cycle an individual selection was made in the field, marking plants with outstanding characteristics (vigor, sanity, height) in the field, which after being harvested were individually selected according to the shape of the bulb, number cloves, consistency and color of cataphylls using an enhancement scheme similar to that employed by ^{Macías et al. (2014)}. From the second year they were carried out for six consecutive cycles in experimental plots of the Experimental Field Zacatecas of the National Institute of Forestry, Agriculture and Livestock Research located in the municipality of Calera, Zacatecas, Mexico, at a height of 2 198 m above sea level, north latitude 22° 54’ 24.32” and west longitude 102° 39’ 34.92”.

Characteristics of the plant

Plants of the Barretero variety have a semi-erect growth habit (^{PPV and FRA, 2007}), like San Marqueño (^{Macías et al., 2010}), contrasting with Calerense and Diamante varieties which have erect habit (^{Reveles-Hernández et al., 2011}; ^{Macías et al., 2014}) with a maximum average of 10 active leaves reached at 195 days after sowing (dds) which sharply contrasts with Calerense (17.8 leaves), the maximum height of the plant (61 cm average) is reached around 175 dds, which is 17 cm higher than the average for Calerense plants, the dimensions of the false stem are 21.2 cm in height and 18.4 mm in diameter at the basal part, which are usually reached at 110 dds, the leaf arrangement is semi-erect, its dimensions in an adult plant (210 dds) are on average 2.6 and 62.5 cm wide and long respectively. Plants of the Barretero variety produce a curved flower stalk and even present bulbils in the inflorescence, they are generally higher plants than the Calerense variety, but less abundant and longer leaves (^{Reveles et al., 2011}) (Table 1).

Table 1 Principal characteristics of garlic plants of the Barretero variety obtained in the Experimental Field Zacatecas-INIFAP during the cycles 2006-2007, 2011-2012, 2012-2013 and 2013-2014.  

Bulb characteristics

The bulbs of the Barretero and Calerense varieties show similar characteristics: both have an oval and circular shape in their longitudinal and transverse sections respectively; its base is flat and covered by several white false leaves that have anthocyanic striations (vertical streaks of violaceous pink coloration); however, the average number of cloves in the Barretero variety is 13, fewer than Calerense having an average of 16 cloves (^{Reveles-Hernández et al., 2011}). Other similar features include white to cream pulp and are individually covered by a dark pink coloring sheet; they are radially distributed and disposed in an inserted way in the stem; on average it has nine outer cloves and four inner cloves (Table 2).

Table 2 Main bulbs characteristics of the Barretero garlic variety obtained at the Experimental Field Zacatecas of the INIFAP during 2006-2007, 2011-2012, 2012-2013 and 2013-2014 cycles.  

The culture cycle of Barretero variety is considered intermediate length, lasting 220 days to harvest, similar to Platero (^{Reveles-Hernández et al., 2011}); this feature is favorable compared to other varieties with white bulbs recommended for Zacatecas that have an extended culture cycle (240 days) (^{Macías et al., 2014}) and is comparable to other varieties of white bulb recommended for southern Zacatecas such as San Marqueño with a 210 days cycle (^{Macías et al., 2007}). Among the advantages compared to other varieties of the same type planted in the region, Barretero stands out for having greater homogeneity in the shape and size of bulb; and its relative density (weight per bulb of the same caliber) is higher than the Calerense variety (^{Reveles et al., 2014}) (Table 3).

Table 3 Average weight (g) of bulbs of Barretero variety according to its size (^{Reveles et al., 2014}).  

Compared with the Calerense garlic variety harvested in the state of Zacatecas, it has been found that Barretero shows a slightly lower protein concentration, while the percentage of dietary fiber was higher in Barretero as well as the percentage of soluble solids. However, the total titratable acidity was higher in Calerense than in Barretero (Table 4) (^{Figueroa-González et al., 2015a}; ^{Figueroa-González et al., 2015b}).

Table 4 Comparison of the nutritional characteristics of garlic bulbs between Barretero and Calerense variety (^{Figueroa-González et al., 2015a}; ^{Figueroa-González et al., 2015b}).  

Table 5 shows the yields obtained during four evaluation cycles of the variety under experimental conditions in the Experimental Field Zacatecas. The Barretero variety showed an average potential yield of 23.98 t ha^-1 in contrast to that obtained by Calerense with an average of 19.96 t ha^-1 during the four evaluated crop cycles, which represents a 20% increase in yield in Barretero compared to Calerense.

Table 5 Yields (kg ha^-1) of the Barretero variety compared to Calerense during four crop cycles in the state of Zacatecas.  

Adaptation of the variety

The Barretero garlic variety adapts favorably to the conditions of the Zacatecas plateau and similar areas, with altitude equal to or greater than 2 000 masl.

In evaluations of the Barretero variety carried out in the state of Tlaxcala, it has been observed its adaptation and yield compared to the genotypes established in the garlic producing region of that state, located in the municipality of Terrenate at a height above sea level of 3,115 meters (^{Rojas and Reveles, 2013}), where it reached a yield of 16.5 t ha^-1, this is 96% (8.1 t ha^-1) more than the creole material used as a control, which produced only 8.4 t ha^-1.

The results of the yield behavior of the Barretero variety in the state of Zacatecas and Tlaxcala indicate that this garlic variety is an alternative for jaspeado garlic producers for regions with similar climatic characteristics of the center and north of the country, where rainfall is predominant in summer and there are low temperatures and frost in the winter with average minimum temperatures below 4 °C (^{INEGI, 2016}).

Various yield evaluations conducted with the Barretero variety compared to the Calerense variety have shown that Barretero yielded more by producing 24 448 kg ha^-1 while Calerense produced only 20 714 kg ha^-1 during the 2015-2016 cycle under experimental conditions in Calera de V. R., Zacatecas, this yield was closely related to the bulb size (^{Hernández et al., 2016}). In commercial terms Barretero variety has produced higher percentage of commercial bulbs than other clones generated by the National Institute of Forestry, Agriculture and Livestock Research in Zacatecas (^{Reveles et al., 2016}).

Availability of seed

At the Experimental Field Zacatecas of the INIFAP, original seeds are available and work is carried out to preserve and increase seeds for commercialization and make it available to the producers of this vegetable.