In the cross-breeding to develop a new genotype plant, it is more important to distinguish fertile pollen grains from sterile ones for the research. The genetic feature in the plant is related with the appearance of the pollen. The proposed quantities of shape and pattern on the pollen by the image processing are insufficient for distinction between the former and the latter, since appearance of hybrid pollen grains by the cross-breeding can not be estimated previously. The paper proposes the color index and the color index diagram as a new quantities for the estimation of the pollen grains. The color index shows a quantity of the feature color of the every pollen by using the xy color chromaticity diagram. The color index diagram shows an area of distribution on all of the color indexes. By the color index and the color index diagram, it can be measured that the pollen grains are fertile or sterile as the genetic trends of the plants. In the paper, it is shown that the color index and the color index diagram are more effective to distinguish between fertile and sterile pollen grains in some samples from the new genotype plants.
