Three cultivars and 12 haploid-derived experimental lines of burley tobacco (Nicotiana tabacum L.), with levels of nicotine ranging from very low to normal, were field-tested in 1974 and 1975 for resistance to the green peach aphid, Myzus persicae (Sulzer), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer). There was no relationship between nicotine level and populations of flea beetles or of alate or apterous green peach aphids. There were not great differences in populations of flea beetles on the various cultivars and lines of burley tobacco, but there were large differences in populations of apterous green peach aphids. Kentucky 14, a cultivar with normally high levels of nicotine, had high populations of apterous green peach aphids, while Burley 21 with similar levels of nicotine had very low populations, and low-alkaloid (LA) Burley 21 with very low levels of nicotine had high populations in 1974 and low populations in 1975. Aphid populations were not related to nicotine content in the 12 haploid-derived experimental lines. These lines originated as haploid plants cultured from immature anthers of the F1 hybrid of a LA Burley 21 x Burley 21 cross. Theoretically, the haploid plants could have been of any genetic combination that could have developed in the male gametes of the F1 hybrid. Because the haploid-derived lines were selected only on the basis of alkaloid potential, other factors presumably differed between lines within the same alkaloid populations.

(Full article published with kind permission from "Tobacco International")