A Dominant Gene for the Banded Cucumber Beetle Resistance in Lettuce

Banded cucumber beetle (Diabrotica balteata) is an insect pest of lettuce in Florida and needs pesticide application for control. The romaine lettuce (Lactuca sativa) cultivar ‘Valmaine’ is resistant to the banded cucumber beetle. A population developed from a cross between ‘Valmaine’ (resistant) and ‘Okeechobee’ (susceptible) was used for determination of the inheritance for the resistance. The segregation ratio was found to be 3(resistance) : 1(susceptibility) in the F₂ and 1(homozygous resistance) : 2(heterozygosity) : 1(homozygous susceptibility) among the F₃ families. It appears that the resistance is controlled by a dominant gene in ‘Valmaine’. The bulked segregant analysis (BSA) is being conducted to map the resistant gene with amplified fragment length polymorphism (AFLP) markers, target region amplification polymorphism (TRAP) markers, and single nucleotide polymorphism (SNP) markers. Markers closely linked to the resistant gene will be useful for marker-assisted breeding for development of new lettuce cultivars with improved yield and horticultural traits and resistance to the banded cucumber beetle resistance.