Marker-assisted selection in breeding silkworm strains with high tolerance to fluoride, scaleless wings, and high silk production.

In the silkworm (Bombyx mori), tolerance to fluoride and scaleless wings are controlled by the dominant gene Dtf (dominant tolerance to fluoride) and recessive gene nlw (no Lepidoptera wings), respectively, and these genes have been mapped by using simple sequence repeat and sequence tag site markers. Marker-assisted evaluation and selection of silkworms with fluoride tolerance and scaleless wings were used for predicting fluoride resistance and scaleless wings in backcrossed animals. A silkworm strain was bred using this method, and its economic characteristics were found to be similar to those of commercial silkworms. These methods will therefore be useful for silkworm breeding programs and in screening for two or more characteristics of interest for segregating populations.