Obtaining the hybrid

For the development of the Olmeca hybrid, the applied genotechnical method consisted of: performing a simple cross to generate the F1 hybrid; from the RIM 76 A x EET 400 genotype. The RIM 76 A genotype corresponds to a clonal selection of a creole genotype from Chiapas, Mexico, while the EET 400 genotype corresponds to a commercial clonal selection from Ecuador (^{Escobar, 2008}).

The crossing of these parents originated a family (1995) and their descendants generated 30 plants (1996). Due to the heterosis of the F1 hybrids, the evaluations were per individual. As a result of this selection, the Olmeca hybrid was obtained, which has been reproduced by clonal multiplication by graft to maintain its genetic identity.

From this family of F1 hybrids, the Olmeca clone was selected which was evaluated from 2006 to 2016 in the El Morralero farms in the municipality of Comalcalco, Los Pinos in the municipality of Cunduacan and in Ostitan in the municipality of Huimanguillo in the state of Tabasco.

Among its morphological characteristics, its leaves are large and sharply shaped, medium green, with tender, light red leaves and its apex_is predominantly apiculate. Its flowers have pedicels with moderate pigmentation, long and moderately wide sepals. Its sepal pigmentation is weak and in some cases absent. The ligule is yellow in color with intensely pigmented staminodia. Its fruits are large (up to 20 cm) with elliptical shape (Figure 1), obtuse apex and weak basal constriction. The surface of the fruit is smooth or slightly rough and has shallow grooves. The color of the fruit is yellow when ripe and green/purple in the juvenile stage (Figure 1). The seed is covered with white pulp and medium sweetness. The number of seeds per fruit is high (40 seeds on average), oblong in shape and large. The hue of the cotyledons is mostly dark purple.

Figure 1 Fruits of the Olmeca hybrid genotype. a) the cacao tree is shown with tender fruits; b) ripe fruits are shown; and c) seeds with mucilage and bare seeds. 

Reaction to moniliasis

Resistance to moniliasis of the Olmeca genotype in the field is of the order of 85%, while in direct inoculation tests they have shown 80% resistance to this disease, compared to the regional creole genotype, which presented 50% incidence to moniliasis.

Yield and fruit index

The evaluations of the yield in plants during a period from 2006 to 2016 have indicated that up to 46 fruits can be obtained per tree free of diseases and presented an average fruit index of 16 (2013-2016), this indicates that with this number of fruits can produce one kg of dry cocoa (Table 1). Compared to the regional creole control, it presented a very high fruit index since 30 pods are required to obtain one kg of dry cocoa.

Organoleptic characteristics

The tasting of dry fermented cocoa bean and cocoa paste has presented notes of cocoa, fresh fruit, nuts, fruity, sweet malt caramel and dried fruits (Azpeitia et al., 2018). These attributes make it of commercial interest for its exploitation for the production of chocolates of origin of the variety, characteristics that are not yet used in Mexico (Table 2). The genotype known as ‘National’ from Ecuador, which possibly comes from the local Amazonian population and with some hybridization with Trinitarian types, is distinguished by its special aroma, with floral and dried fruit notes (^{CAOBISCO/ECA/FCC, 2015}).

Conclusions

The Olmeca clone represents a quality cocoa as it highlights its high yield. with an index of ear of 16. Additionally it has resistance in 90% to the black spot and 86% to the moniliasis. These values exceed the regional creole control, as well as the experimental varieties with code 420093 and 330093.

Additionally, the Olmeca clone stands out for its organoleptic notes for its possible use in Mexico and in the world as Origin chocolate. Olmeca, has been registered in the National Catalog of Plant Varieties of the National Seed Inspection and Certification Service (SNICS) with number CAO-008-230218 and breeder's title number 2270.