Table 1.

Responses to Cry1Ac of resistant (AY2 and QX7), susceptible (SCD), F₁ (resistant × susceptible), and backcross (F₁ × susceptible) larvae of H. armigera.

Source	LC50 (95% FL)*	Slope ± SE†	n	Resistance ratio‡
Strain
AY2	50.6 (34–94)	1.1 ± 0.2	336	1200
QX7	18.5 (13–31)	1.1 ± 0.1	336	460
SCD	0.0406 (0.033–0.049)	1.9 ± 0.2	384	1.0
F1
AY2 × SCD	17.6 (13–27)	1.4 ± 0.2	288	430
QX7 × SCD	6.42 (4.0–13)	1.5 ± 0.2	240	160
Backcross
(AY2 × SCD) × SCD	1.94 (1.3–3.1)	0.84 ± 0.06	624	48
(QX7 × SCD) × SCD	1.67 (1.2–2.3)	0.94 ± 0.08	528	41

^*Concentration (μg toxin/cm²) killing 50% of larvae and its 95% fiducial limits.

^†Slope of the concentration-mortality line and its standard error.

^‡LC₅₀ for a strain or progeny from a cross divided by LC₅₀ for susceptible strain SCD.