The sensibility of different genotypes of Corn to the fertile levels of field was varied as follows:
In lower fertile level field, the area of green leaves and the leave area per plant were decreased and the periods of plant growthg were prolonged, but plant height, the height of ear node and leave number had little change. The genotypes which were high in yield under the lower fertile field had good endurance to the barren field. The sensibility of hybrids of single-crosses to different fertile levels of field was closely associated with their parent lines.