Table 3.

Resistance to four Bt toxins produced by exposing a hybrid multifamily strain (HMF) to toxin Cry1Aa

Source	Generation	n	Toxin	Conc., mg/liter	Mortality,* %
5 families (pooled)	F1	80	Cry1Aa	10	93
		83	Cry1Aa	100	91
HMF	F3†	280	Cry1Aa	100	77
HMF	F5‡	102	Cry1Aa	100	0
	F5	100	Cry1Ac	100	6
HMF	F7	100	Cry1Ab	100	2
	F7	100	Cry1F	10§	0

^*Mortality after 5 days was adjusted for control mortality. 

^†Eleven F₁ survivors of exposure to Cry1Aa were pooled and mated among themselves for two generations to produce F₃; mortality of F₃ was not significantly different from 75% (χ2 = 2.45, df = 1, P > 0.1). 

^‡Fifty-eight F₃ survivors of exposure to Cry1Aa were pooled and mated among themselves for two generations to produce F₅. 

^§Milliliters of formulated Cry1F per liter.