Fig. 3. Mean values of RPF and cross-pollination against distance in open and sorghum experiments. High sorghum crop decreased the rate of pollen flow and cross pollination,and it shortened the incidence distances, 35 m in the open and 20 m in the sorghum experiment. RPF, rate of pollen flow, indicates the percentage of pollen load at differentdistance locations for each direction. Open, pollen flow freely without barrier; Sorghum, sorghum barrier to block pollen flow. Dotted lines indicate the cross-pollination rateof 0.9% in the right panel. Vertical lines above bars indicate the standard errors of means (n = 8 directions).