The standard of corn hybrid must reach the second-class product of national standard, that is, the purity is not less than 96%, the cleanliness is not less than 98%, the germination rate is not less than 85%, and the water content is not higher than 13%.

Maize hybrids:

Two or more maize inbred lines or varieties with excellent characters and great genetic differences are crossed, and the offspring are hybrids.

The purpose of popularizing planting maize hybrids is to increase the yield per unit area. Maize hybrids are different from common varieties and have obvious heterosis:

(1) As long as the combination selection and cultivation methods are appropriate, the yield of hybrid corn with high yield and large yield increase is 20-30% or even more than that of common varieties under the same conditions.

(2) Strong resistance and wide adaptability. Maize hybrids have the advantages of disease resistance, lodging resistance, drought tolerance, barren tolerance and strong adaptability, which are incomparable to any farm variety.

(3) The plant height, plant type, ear position, heading date, ear size, ear type and grain type of a robust and uniform common corn variety are always uneven among different plants of the same variety. The hybrid is neat, with thick stems and developed roots, which can not only improve the yield per unit area, but also stabilize the yield. Practice has proved that popularizing hybrid planting is an effective way to increase production.