Agronomic behavior of the Gacela H72 hybrid in localities of Valles Altos

The agronomic behavior of the hybrid Gacela H72 was evaluated experimentally and in lots of commercial production from 2009 to 2016 in 25 representative localities of environments of deficient, intermediate and favorable weather or with irrigation of aid, with the purpose of studying better the performance of the global performance and that of the interaction genotype x environment of performance. At a global level, the yields varied from 4.3 to 11.2 t ha^-1 and represent values of 85 to 126% with respect to the joint yield of commercial controls H-48, H-70, AS-722 and the creole variety.

The number of days at male flowering ranged between 75 and 109, corresponding to sites located at altitudes of 2 250 and 2 650 m respectively; that is to say, at higher altitude, the emergence, development of the spike and dispersion of the pollen is slower due to lower temperatures of the place. Regarding plant height, Gacela H72 showed a plant size that varied from 170 to 230 cm the highest plant height is usually associated with higher altitude and very humid environments. The planting that showed Gacela H72 ranged between 3 and 9%, which represents values of minimum to moderate lodging. The stockings; through, localities for yield, male flowering, plant height and planting were 7.9 t ha^-1, 96 days, 210 cm and 6%, respectively. Through the test environments, Gacela H72 was 14% higher in performance than the average of commercial controls (Table 2).

The agronomic management technology for the commercial production of the Gacela H72 hybrid is the same as that indicated in Technical Booklet No. 13 for the production of H-70 (^{Arellano et al., 2011}).

Seed productivity of the progenitors of the Gacela H72 corn hybrid in localities of High Valleys.

In the Valley of México Experimental Field located in the town of Coatlinchan, Texcoco, State of Mexico at 2 240 meters above sea level, experimental grain yields were recorded for progenitor lines M-54, M-55 and CML-242 of 2.6, 2.5 and 2 t ha^-1, respectively. In terms of yield and seed vigor characters, the lines indicated above were classified as stable when evaluated in three locations of High Valley and Bajío (^{Hernández, 2018}). Regarding the performance of the female progenitor M-55 x M-54 established in irrigated field at sowing date of May 20 in the town of Coatlinchan (2 230 meters above sea level), State of Mexico, a production of 10 t ha^-1 (^{Virgen et al., 2009}).

On the other hand, it was found that in plantings with producers from Espiritu Santo-Ixtacuixtla and Francisco Villa, both of Tlaxcala, located at altitudes of 2 430 and 2 530 m respectively, the simple female crossing yielded 6.5 and 6.2 t ha^-1, respectively, with the population density of 83 thousand plants ha^-1 and sowing date of april 19, these yields exceeded 1.5 and 3 t ha^-1 of the female crosses of the commercial hybrids H-40 and H -50, respectively (^{Virgen et al., 2009}; ^{Virgen et al., 2010}). In the towns of Texoloc, Benito Juárez and San Nicolas Panotla in the state of Tlaxcala at altitudes of 2 225, 2 530 and 2 200 m respectively, the female parent (M-54 x M-55) yielded 8.6, 6.9 and 6.4 t ha^-1 respectively, while the male progenitor (CML-242 x CML-354) yielded 7, 3.5 and 3.9 t ha^-1, respectively (^{Virgen et al., 2013}).

On the other hand, in the town of San Miguel The Presa, Tlax. (2 600 meters above sea level) the male parent surrendered 11.9 t ha^-1 with a high population density of 68 thousand plants per hectare and with a low density of 42 thousand plants, 7.89 t ha^-1, in Tlaxco, Tlax. (2 580 meters above sea level) produced 8 t ha^-1 with high density and 6.83 with low density. In the town of Panotla, Tlax. (2 200 meters above sea level) the yields with the high and low densities were of 7.5 and 7.2 t ha^-1, respectively, while in Francisco Villa (2 530 meters above sea level), the male progenitor produced 7.4 t ha^-1 with high density and 6.2 t ha^-1 with low density. Based on the previous results, it is possible that the male parent CML-242 x CML-354 can act as a female parent in localities where its yield is higher than 6 t ha^-1 since it has a plant type of less height than M-55 x M-54, which would facilitate the desespigue work and achieve greater genetic purity of the certified seed.

The previous results indicate the possibility of obtaining very favorable seed yields of the parents and the Gacela H72 hybrid in localities located between 2 200 and 2 600 masl, which makes the multiplication of certified seed of this new hybrid of corn in a reliable and profitable way. Localities of the High Valleys.

The recommended sowing period for the production of certified seed in the Central Highlands of Mexico is established in april, while the female-male sowing ratio is 6:2, where the male parent should be planted a week before than the female, both under the population density of 65 000 plants ha^-1. The beginning of the detasseling period marks the emergence of the spikes, it is recommended to carry out this activity in six days and to consider in the last, the elimination of the spike (^{Arellano et al., 2010}).

Conclusions

In terms of the productive potential of the regions of the central Highlands of Mexico and the adaptability of Gacela H72, it is established that there are at least 75 000 ha in the state of Tlaxcala, 150 000 in Puebla, 200 000 in the State of Mexico and 90 000 in Hidalgo, where the new maize hybrid can participate successfully to increase yields under rainfed or irrigated crops