Two Genes for Cucumber Beetle Resistance in Muskmelon

Abstract

Abstract In the early 1970s, a study was begun to find resistance to feeding in muskmelon, Cucumis melo L., by banded cucumber beetles, Diabrotica balteata LeConte. Bitter seedlings were observed to be more susceptible to feeding than nonbitter seedlings. We noticed reduced damage levels in both bitter and nonbitter seedlings in 1974. Genetic study of resistant materials showed that in addition to the recessive form of the bitter gene, bibi , a 2nd recessive gene, cbl cbl , conditioned reduced seedling susceptibility. Subsequent tests involving spotted ( Diabrotica undecimpunctata howardi Barber), striped [ Acalymma vittata (Fabricius)], and banded beetles on leaf disks of several C . melo cultivare showed that homozygous double recessive, bibi cblcbl , plants were more resistant to all 3 species of cucumber beetles than nonbitter, bibi Cbl — and bitter Bi—Cbl — plants. This double-recessive resistance provides muskmelon breeders with germplasm which can be incorporated into breeding lines and hybrids.