Resistance in Glabrous-type Cucumis melo L. to Whiteflies (Homoptera: Aleyrodidae)

Abstract

In 1995, 15 melon cultigens, Cucumis melo L., were compared over planting dates and insecticide treatments in a split-split plot experiment for susceptibility to whitefly, Bemisia argentifolii Bellows & Perring, damage. In this test, glabrous melons were found to reduce numbers of all stages of whiteflies on the crop. Glabrous occurred as a mutation in western U.S. shipping type cantaloupe, ‘SR91’. Glabrous was crossed with TAMSun (a commercial-type cantaloupe (or muskmelon) cultigen, C. melo Group Cantalapensis) to study the inheritance of resistance to Bemisia sp., examine the relationship between the glabrous leaf trait and whiteflies, and to begin development of a glabrous melon adapted to South Texas that is resistant to Bemisia. In 1996 and 1997, F2 glabrous and pubescent selections were compared to ‘Explorer’ and ‘Cruiser’ in imidacloprid-treated and non-treated main plots in a split-plot design. The F2 progeny were from a TAM Sun (selfed selection out of ‘Sunshine’, an F1 hybrid from Ferry Morse Seed Company) × ‘SR-91’ glabrous genotype (single gene recessive trait) cross, backcrossed to TAM Sun. Whitefly counts were made through the season and yield data were collected to measure plant response. The glabrous-leaf melons consistently had lower whitefly adult and nymph population densities than commercial pubescent-leafed cultigens. Also, the glabrous F2 was not significantly different in yield compared with two commercial cultigens. Glabrous-leaf melons had significantly shorter vine length and % sugars in the spring of 1997, but not in the fall of 1996. In 1998, the F3 of the same backcross was evaluated on plastic mulch beds under field conditions in Georgia and the F3 progeny was described.