Two winter wheat cultivars are known to differ in sensitivity to metribuzin: TAM W-101 (tolerant) and Vona (sensitive). Their reciprocal F1, reciprocal F2, and backcross populations were compared to determine the genetic expression of metribuzin sensitivity. TAM W-101 showed a much wider range of response to metribuzin than Vona with little overlap between the two distributions. Both sets of reciprocal F1 and F2 populations resembled Vona in metribuzin response, but the variances of maternal TAM W-101 populations exceeded those of maternal Vona populations. Genetic segregation in metribuzin response was expressed in TAM W-101/Vona F2 but not in Vona/TAM W-101 F2. The greater variability observed in the metribuzin-tolerant parent TAM W-101 and maternal TAM W-101 populations could not simply be interpreted as the result of differential sampling of male and female gametes from TAM W-101.
