Abstract

The
objective of this work was to determine the affi nity and
effect of Azospirillum in corn. This bioassay was conducted
in the state of Mexico, México, during the spring – summer
cycle of 2009. The root system of corn Palomero Toluqueño,
Cacahuacintle, Cónico, Chalqueño and H-20, and of Teocintle,
was collected, and after isolation and purifi cation of
strains outstanding in their nitrogenasa activity (N’asa), were
reinoculated aseptically in the same varieties at the seedling
stage (13 days) under hydroponic culture. Root volume was
determined, and also used to determine bacterial populations
and N’asa at 60 dde, in corn and Teocintle. Azospirillum did
not affect root volumen in relation to nitrogen fertilization,
but the comparative study showed that strains isolated from
Cónico and Chalqueño corn, in addition to Teocintle, formed
more root tissue in Chalqueño corn. Despite that the largest
bacterial population was obtained with the strain isolated
from H-28 ans inoculated on corns Chalqueño, H-28 and
Cónico, the highest N’asa was recorded with strains isolated
from H-28, Palomero Toluqueño and Chalqueño, inoculated
on corn Chalqueño. There was a degree of affi nity, or effect
of the homologous strains, between Azospirillum obtained
from corns H-28 and Chalqueño and their re-inoculation on
the same varieties, evaluating the number of azospirills and
N’asa, and a survey of Azospirillum from recent corns, for
ancestors of the same cereal.
Keywords: Diazotrophic bacteria, nitrogen biologic fixation, cruise inoculation, homologous strains.