Resumen Con el fin de investigar el efecto de cuatro biosólidos de las industrias láctea, maltera, jabonera y papelera sobre el crecimiento y producción de biomasa de plántulas de Vicia faba L., se realizaron mezclas de biosólido:suelo en proporciones 20:80, 40:60 y 60:40. Se realizaron análisis fisicoquímicos y microbiológicos a cada biosólido y las mezclas. Los biosólidos mostraron diferencias en la presencia (NMP) de coliformes fecales de 3 a 1 100 Salmonella sp., de 2 a 3 y de 0 a 16 huevos de helmintos por g de sólidos totales. La concentración (mg kg-1) de metales pesados en cobre fue de 0.7 a 1.9, cromo de 0.8 a 2.4, cadmio de 0 a 0.6, zinc de 4.3 a 8.6, níquel 1.2 a 3.8 y plomo 1.3 a 5.7, sin arsénico y mercurio. Los contaminantes fueron inferiores a los límites permisibles según la SEMARNAT (2002), además, entre los biosólidos el pH varió de 7 a 9.8 y la materia orgánica (MO) de 0.3 a 6.2%. Los biosólidos de la industria láctea y malta incorporados al suelo modificaron el pH de 8.1 a 7.4, incrementaron la MO de 1.2 a 3.5%, el nitrógeno total de 7 a 35 mg kg-1 y el fósforo disponible de 5 a 25 mg kg-1. A 30 días después de la siembra en invernadero, las plántulas de V. faba que crecieron en suelo con el biosólido de la industria láctea en la mayor proporción incrementaron la producción de biomasa en 1 145% y la longitud en 342%.

Abstract In order to investigate the effect of four biosolids from the dairy, malt, soap and paper industries on the growth and production of biomass of Vicia faba L. seedlings, biosolid:soil mixtures were made in ratios 20:80, 40:60 and 60:40. Physicochemical and microbiological analyses were performed on each biosolid and mixtures. Biosolids showed differences in the presence (MPN) of fecal coliforms from 3 to 1 100, Salmonella sp., from 2 to 3 and from 0 to 16 helminth eggs per g of total solids. The concentration (mg kg-1) of heavy metals in copper was from 0.7 to 1.9, chromium from 0.8 to 2.4, cadmium from 0 to 0.6, zinc from 4.3 to 8.6, nickel from 1.2 to 3.8 and lead from 1.3 to 5.7, without arsenic and mercury. The contaminants were below the permissible limits according to SEMARNAT (2002), in addition, among biosolids the pH varied from 7 to 9.8 and organic material (OM) from 0.3 to 6.2%. Biosolids from the dairy and malt industries incorporated into the soil modified the pH from 8.1 to 7.4, increased OM from 1.2 to 3.5%, the total nitrogen from 7 to 35 mg kg-1 and the available phosphorus from 5 to 25 mg kg-1. At 30 days after sowing in the greenhouse, V. faba seedlings grown in soil with the biosolid from the dairy industry in the highest ratio increased biomass production by 1 145% and length by 342%.

ABSTRACT Ustilago maydis is a basidiomycete known as the causative agent of 'common smut', worldwide disease of maize that is recognized by the galls it forms, which have considerable potential as a gourmet food. Results of infection are quite variable, even under optimal greenhouse conditions. In order to find pathogenic strains able to be used as a highly infective and stable inoculum for the successful production of galls either in greenhouses or in the field, ears with gall symptoms containing teliospores were recovered from maize plants. The teliospores were suspended in water and plated on nutrient-rich medium. Twenty-six colonies developed, containing three types of yeast-like colonies: saprotrophic, pathogenic, and solopathogenic. DAPI staining confirmed the presence of solopathogenic strains with diploid sporidia. Groups of different mating types were found when pairs of the 26 strains were arranged resembling partial-diallel combinations. Amplification of the partial b locus revealed that the strains found harbor the alleles b3 and b4, allowing the formation in dikaryotic strains of heterodimeric regulatory proteins associated with fungal development and pathogenicity. In this study, we isolated compatible haploid and solopathogenic diploid strains for their high capacity for inducing smut.