This indicated that there was a strict reproductive isolation between maize and Coix L. and style or embryo sac incompatibility was the crossing barrier between maize and Coix L.

• 玉米与薏苡杂交时, 薏米花粉管能到达玉米花柱基部, 而川谷花粉管却在花柱中停止生长, 杂交障碍与薏苡种类有关。