Yield

The yield data of dry matter of grain, straw, total and harvest index are presented in Table 2. Statistical differences existed (p≤ 0.05) in most of the treatments evaluated, several studies in wheat have shown differences due to the plant-microorganism-environment interaction (^{Khalid et al., 2004}; ^{Ferraris and Couretot, 2006}; ^{Arias, 2007}). Regarding grain production, the highest yield was obtained in the T1 treatment (regional control without biofertilizer and with 100% fertilization) and the lowest in the T2 treatment (control without biofertilizer and with 50% fertilization), in the crop of wheat reduce fertilization causes a reduction in the yield of 1 475 kg ha^-1 so this practice is not recommended. The application of bacteria in the wheat yield had a small effect if the T3 vs T2 were compared and negative if the T4 vs T2 were compared, the low yields in T4 could be due to the negative effect of certain plant-microorganism relationships in inhibiting the radical development and reduce the efficiency in the intake of nutrients such as N and P, especially in alkaline P soils (^{Afzal et al., 2005}; ^{Barea et al., 2005}; ^{El-Sirafy et al., 2006}).

A greater effect on wheat yield was observed with the mycorrhizae applied in treatments T6 and T5, which coincides with that reported by ^{Kumar et al. (2011)}, in field trials with two wheat genotypes had increases of up to 25.8% when the seeds were inoculated with mycorrhizae. In this case, T6 could be an option to reduce the risk of environmental contamination by applying only 120 kg ha^-1 of N. In this case, AMF had a greater effect on wheat yield than bacteria, in this respect ^{Peltzer et al. (2003)}, observed a null effect of the inoculation on the yield and weight of wheat grain with Pseudomonas fluorescens. In addition, another cause may be the immobilization of nutrients when microorganisms decompose organic waste (^{Grageda-Cabrera et al., 2003}).

^{Bolletta et al. (2002)}, in plots of wheat inoculated with mycorrhizae obtained between 15 to 18% more yield than the unfertilized controls, in this trial the differences disappeared when compared with the treatments fertilized at 100%.

Regarding the production of total dry matter, all treatments exceeded T2, which was related to greater production of straw. The highest production was obtained in treatments T1 and T6. The reduction in fertilization caused a reduction in the total biomass of 4 751 kg ha^-1. This is confirmed by the harvest index (IC), which is an indicator that provides information on grain production compared to all the biomass produced. The data show that the inoculation of biofertilizers affected the harvest index, treatments T3 (bacterium 2709) and T8 (mycorrhizae PI63) negatively affected this parameter, the crop produced more straw than grain compared to the other treatments, which leads to an efficient use of nutrients.

Total nitrogen

In the Table 3 shows the assimilation of total N. The statistical analysis indicates that there are significant differences similar to those observed in the total dry weight (Table 2). Absorption of N is directly related to performance (^{Sprent, 1987}).

Regarding the content of N in grain, the treatments T5 and T6 were statistically equal and surpassed only by the treatment fertilized to 100% of the dose, reason why these biofertilizers contributed to the accumulation of N (protein) in the grain. This same effect was observed for total N in the plant, with values between 205 to 212 kg N ha^-1. The treatments that accumulated less amount of N in grain were T4, T8 and T9, which corroborates that the biofertilizers do not work of generic form, these must be generated for specific regions of production.

Regarding the harvest index of N (ICN), it was significantly affected by biofertilizer treatments. The Tukey test establishes five groups of treatments with a significant response to ICN, the largest is associated with ICN> 0.73 and the lowest ICN< 0.67. The highest ICN was 0.75, which indicates that the plant used 75% of its total nitrogen for grain. But it is not associated with the highest grain yields as observed in the fertilized treatment with an ICN of 0.72. The application of biofertilizers influenced the assimilation of N and the content of N in grain; these characteristics are related to the amount of protein, carotene content and quality (^{Degidio et al., 1993}). On the contrary, the dilution of the N content in grain causes an increase in the percentage of white belly and reduces the quality (^{Mahdi et al., 1996}).

Nitrogen derived from fertilizer (N ddf) and percent utilization of nitrogen fertilizer (% UFN)

The results of the amount of N in the plant derived from the fertilizer are presented in Table 4. The treatment that accumulated the greatest amount of N of the fertilizer was T1 with a total of 83 kg N ddf ha^-1, which indicates that the Wheat took 136 kg ha^-1 N from the soil. This treatment received twice as much nitrogen fertilizer as the other treatments, which was reflected in a greater assimilation of N ddf. T5 and T5 treatments followed with 48 and 53 kg N ddf ha^-1 each, these treatments take advantage of more N of the soil with 157 and 159 kg ha^-1, respectively. The grain presented greater N ddf than straw.

The results of the percentage of N ddf and UFN are presented in Table 5. Of the total N assimilated by the crop, less than 40% came from the nitrogen fertilizer and the rest of the soil. There was a significant difference (p≤ 0.05) in the values of the percentage of N ddf in the crop between biofertilization treatments. The highest values were obtained in T1, with 38% N ddf, which raises the need to review the current application form of the fertilizer to improve its use. Regarding the effect of biofertilizers, those that contributed to the plant assimilating a greater quantity of Nddf were the treatments with mycorrhizae T5 and T6, with 23 and 25% N ddf.

The percentage of UFN indicates the amount of N that assimilated the crop of the total of N applied as fertilizer. It was observed that inoculation with T5 and T6 mycorrhiza contributed to the plant assimilating a greater amount of N than applied as fertilizer, improving with this the percentage of UFN compared to T1, which had greater availability of N.

The best treatments in terms of percentage of UFN were T6 (Mycorrhiza CH1), T5 (Micorriza INIFAPMR) and T7 (Mycorrhiza DA18), in these cases the plant assimilated 41, 37 and 37% of the total applied fertilizer, representing 52.8, 48.2 and 48 kg N ha^-1, respectively.

Even when inoculation with biofertilizers improved the percentage of UFN, it was low (less than 45%). More 55% of the N applied as fertilizer could not be counted, surely a high proportion was lost as nitrates by leaching or in gaseous form by denitrification, nitrification and volatilization because it is a slightly alkaline soil and retains moisture (^{Vermoesen et al., 1993}; ^{Grageda-Cabrera et al., 2011}; ^{Wanga et al., 2015}).