<span name="style_bold">Effect of pollen dispersion in corn seed production, in Texcoco, México. </span>In order to find out how the pollen of corn is dispersed in a seed production field without isolation, and the implications on genetic quality of the seed, a field test was established (189 m long by 42.5 m wide) during Spring-Summer season of 1992 in Texcoco, Mexico. Three corn populations with contrasting endosperm composition were planted: two of normal field corn and other of sweet corn. The sweet corn variety was surrounded by three rows of the normal corn varieties. The variables measured were plant and ear length, male and female flowering period, percent of normal grain as indicator of the cross of the normal type varieties over the sweet type. Lack of physical isolation and coincidence of flowering periods favored crossing of the varieties. Pollen dispersion and contamination within the field followed a normal distribution; there were variations in the distance and level of contamination due to wind direction and vigor differences of contaminant plants. The lowest grade of contamination was 1% in the central part of the field. According to the response surface obtained, 25 border rows are recommended to obtain seed free of contamination.In order to find out how the pollen of corn is dispersed in a seed production field without isolation, and the implications on genetic quality of the seed, a field test was established (189 m long by 42.5 m wide) during Spring-Summer season of 1992 in Texcoco, Mexico. Three corn populations with contrasting endosperm composition were planted: two of normal field corn and other of sweet corn. The sweet corn variety was surrounded by three rows of the normal corn varieties. The variables measured were plant and ear length, male and female flowering period, percent of normal grain as indicator of the cross of the normal type varieties over the sweet type. Lack of physical isolation and coincidence of flowering periods favored crossing of the varieties. Pollen dispersion and contamination within the field followed a normal distribution; there were variations in the distance and level of contamination due to wind direction and vigor differences of contaminant plants. The lowest grade of contamination was 1% in the central part of the field. According to the response surface obtained, 25 border rows are recommended to obtain seed free of contamination.

Seed purity; pollen dispersion; border rows; outcrossing