Pollen Movement Within and Between Rows to Male‐sterile Soybeans1

Soybean (Glycine max (L.) Merr.) pollen movement was studied by evaluating the frequency of outcrossing on white‐flowered (recessive) male‐sterile plants sampled at various within and between‐row distances from a purple‐flowered (dominant) pollen source. In 1973, five 2.75‐m within‐row segments from 0.0 to 13.75‐m and three between‐row distances from 2‐m to 9‐m were evaluated. The data indicated a linear reduction (from 8.3 to 1.4%) in the amount of purple‐flowered progeny as both within and between‐row distances increased. In 1974, six 6.1‐m within‐row segments from 0.0 to 36.6‐m and 12 between‐row distances from 1.0 to 23.0‐m from the purple‐flowered pollen source were evaluated. The 1974 results indicated that with between‐row distances of at least 7‐m and within‐row distances of at least 12 to 18‐m from the pollen source, little pollen contamination would occur. The percentage of purple‐flowered progeny found at these distances or beyond averaged 0.4%. These results indicated that most outcrossing occurred with surrounding plants, and thus intermating blocks of soybeans could be located adjacent to other soybean experiments or commercial plantings without high levels of pollen contamination.