Abstract: Under the normal field conditions the wheat was inoculated with W-43, W-432, W-91 strains of the associated nitrogen-fixation bacteria for three consecutive years. The result of the test shows that inoculating with an appropriate quantity of bacteria has a remarkable promotion to the vegetative growth, which is mainly indicated as the increase of 0.8-1.0 secondary root in a single plant, of 0.35-0.48 tiller in a single plant, of 1-3cm² in the area of a flag leaf, and of 12% in chlorophyll content. The plant increases by 1-3cm in height, its effective ears 22000-33000/ mu, the number of grain in an ear 1.4-1.5 grain, the weight of a thousand grains 1.4-1.5g, the per unit area yield 20.1-46.4 kg/ mu, and the rate of increase in yield is 6.6-14.2%. At the same time, the quality of wheat is improved.

Key words: Wheat, Associated nitrogen-fixation bacteria, Associated nitrogen fixing effect