This new variety fits very well in low mountain lowland areas and its average grain yield obtained in the different evaluations carried out during the period from 2011 to 2014 was 4.1 t ha^-1, surpassing the original creole by half a ton. Due to its good physical and chemical characteristics of the grain, the ‘V-239 AZ’ is an excellent choice for the preparation of freshly made tortillas, showing high yields of 1.9 kg kg^-1 maize and tortillas 1.5 kg kg^-1 maize, which is due to the fact that the grains are hydrolyzed rapidly and reach similar humidity to those of the hybrids with greater hardness, in addition this new variety presents/displays great amount of anthocyaninas, 582 µg.

In Mexico, 59 maize races have been identified according to the most recent classification based on morphological and isoenzymatic characteristics (^{Sánchez et al., 2000}). The region of the South Pacific, comprised by the states of Guerrero, Morelos, Chiapas and Oaxaca, is characterized by having a great genetic variability of maize and its wild relatives, given its orography that has allowed geographic isolations and consequently isolations of different types of maize (^{Gómez et al., 2010}), where there is genetic diversity that has not been exploited in the form of novel characters and alleles (^{Ortiz et al., 2009}), which could be used to generate new improved varieties, through the application of conventional breeding methods.

As such, native or local creole varieties may have the genetic variability needed to cope with climate change and the generation of specialty maize (^{Bellon et al., 2011}; ^{Guarino and Lobell, 2011}; ^{Mercer et al., 2012}; ^{Ureta et al., 2012}).

Under this context the blue maize stands out in Guerrero for their germoplasmic diversity, giving rise to a great alimentary wealth by the use of the grain, after its nixtamalizacion; however, native blue maize is characterized by undesirable agronomic characteristics, including too high susceptible to lodging, variability in ear height, low yield potential, unproductive plants due to the high asynchrony between their blooms, unequifled grain color which is punished in marketing (^{Rosas et al., 2006}), but also has high food and forage quality that justify recognizing an added value that the consumer should pay; under this perspective, the creole variety ‘V-239AZ’ was generated in which the agronomic problems of the original creole already mentioned have been reduced.

In 2004 the work of genetic improvement was started starting from a population conformed by five collections realized to more than 1 200 m of altitude; was started with the acquisition of a cycle of recurrent selection of half-brothers proposed by ^{Lonnquist (1964)}, in 2006 the blue population was integrated. And in 2008 this population was genetically stabilized and its improvement was restarted with five cycles of convergent-divergent mass selection that gave rise to this variety (^{Gómez et al., 2013}).

The ‘V-239AZ’ is an improved creole variety with agronomic characteristics superior to the regional creole, and was obtained without altering its intrinsic and grain quality characteristics; was registered in 2016 before the National Seed Inspection and Certification Service (SNICS), assigned the number 3391-MAZ-1785-1710616/C, its characterization was made in the Experimental Field Iguala in the sowing cycles, 2012-2013 and 2013 -2014 autumn-winter, based on the maize technical guide (^{UPOV, 2009}) and the graphic manual for the varietal description of maize (^{Carballo and Benítez, 2003}).

The commercial variety ‘V-239 AZ’, is intermediate with a plant height of 261 to 285 cm, 20 to 30 cm smaller than that of regional Creole materials. Its cycle is precocious with 58 and 60 days to the male and female flowering respectively, this variety has rectilinear leaves of medium green color, its spike is compact with 7 to 9 primary lateral branches, stigmas of green-yellow color; cylindrical cone with good coverage of the bracts, is 15 to 20 cm long with 12 to 14 straight rows and 31 to 40 grains per row of blue and semi-toothed texture, its average grain yield is 4.1 t ha^-1.

The blue shade of the grain is more uniform compared to the native materials sowed by the producer. The variety ‘V-239 AZ’ presents an excellent adaptation in the subtropical low mountain regions of the states of Guerrero, Oaxaca and Puebla with altitudes of 1,200-1,700 meters above sea level, with a precipitation of 800 to 1 000 mm, a temperature annual average of 23 to 25 ºC, is adapted to soils that have a pH of 7.5 to 8 and slopes with slopes less than 15%. In evaluations carried out in the last four years (2011 to 2014) in ten different environments of the state of Guerrero, the variety ‘V-239 AZ’ showed a yield that varied from 3.5 to 4.5 t ha^-1, surpassing the original creole in 0.5 at 1 t ha^-1.

The variety ‘V-239 AZ’ has large grains (PCG> 38 g), with reduced hectoliter weight, 68 kg hL and very soft grain endosperm (percentage of floaters less than 87), characteristics that are in accordance with its high percentage of mealy endosperm, of 56% values that are common for native maize and that are inferior to those of improved maize of the state of Guerrero (^{Salinas et al., 2010}). Its proportions of: pedicel 1.96%, pericarp 5%, germ 12.3% and corneal endosperm 25%, are included within those observed in commercial toothed maize (^{González, 2009}).

As for the nixtamalera-tortillera quality, due to the softness of its grain, it requires little time of nixtamalizacion 25 min, consequently the expense of fuel for its processing is reduced. Its nixtamal recorded a reduced solids loss of 1.9% in the cooking liquor (nejayote) and retained on average 30% of pericarp. The moisture of its nixtamal was 48.1%, for the mass 55.5%, freshly made tortillas 43% and 24 h after storage at 4 °C 41.2%, indicating that the grains of the ‘V-239 AZ’ are hydrolyzed rapidly and reach hybrids similar to those of the hybrids with greater hardness, which contributes to the high yields of mass and tortilla of 1.9 kg kg^-1 and 1.5 kg kg^-1 of maize.

Their tortillas 2 h after elaboration, require on average a strength of 262 gF, to break and have an elongation value of 10.2 mm, which qualifies them as soft and elastic tortillas. However, 24 h after storage, they required 347 gF (32.4%) to break and their elongation was reduced to 8.3 mm, making it a good choice for making tortillas.

In the chemical composition of ‘V-239AZ’, it was observed that its grain had concentrations of chemical compounds within the range reported for commercial hybrid maize (^{Salinas and Perez, 1997}), with values that are at the upper end, thus the average content of oil was 5.52%, protein of 9.55%, that in tortillas was increased to 10% due to the concentration that the rest of the compounds suffer after the loss of the pericarp, during the nixtamalizacion and the washing. The values of lysine and tryptophan in endosperm and tortillas were within what was reported for maize of normal endosperm (^{Sierra et al., 2010}).

In whole grain, ‘V-239AZ’ recorded higher amino acid percentages than commercial hybrids, the above is attributed to the greater proportion of the germ in larger grains and possibly to some favorable environmental conditions of the crop (lower population density). The blue shade of the grain (hue = 283°) was increased in tortilla at 310°, grain to tortilla showed a loss of 12 and 14% of lysine and tryptophan respectively and about 50% of anthocyanins (^{Gómez et al., 2013}).

The preservation of the varietal identity of ‘V-239 AZ’ must be carried out in an isolated lot according to the standards established by the National Seed Inspection and Certification Service (SNICS) as distance or time isolation (^{Coutiño, 1993}; ^{Vallejo et al., 2008}), it is suggested to eliminate plants out of type and in prefloration to defuse segregating plants of high ear, bedridden or diseased (Figure 1).

Figure 1 Aspect of plant and cob of the V-239 AZ.