Table 3.

Resistance to Cry1Ac and cross-resistance to Cry2Ab in Cry1Ac-selected strains of H. armigera.

Country (region*)	Location	Year†	Strain	RR‡	Dominance (h) §								Cry2Ab CRR‡‡	References
					Cry1Ac (DC¶)	Cry1Ac (LC50**)	Bt cotton††
China (N)	Anyang	2009	AY9	88	0.00				Zhang et al. (2012a)
China (N)	Anyang	2009	AY16		0.00				Zhang et al. (2012a)
China (N)	Anyang	2009	AY27		0.00				Zhang et al. (2012a)
China (N)	Anyang	2009	AY148		0.00				Zhang et al. (2012a)
China (N)	Anyang	2009	AY440	47	0.04				Zhang et al. (2012a)
China (N)	Anyang	2009	AY335	89	0.13				Zhang et al. (2012a)
China (N)	Anyang	2009	AY-r15	82	0.33	0.63			Zhang et al. (2012b)
China (N)	Anyang	2009	AY423	660	0.64				Zhang et al. (2012a)
China (N)	Anyang	2009	AY441	95	0.66				Zhang et al. (2012a)
China (N)	Anyang	2011	AY2	1200	1.0	0.85	0.94	5.9	This paper
China (N)	Gaoyang§§	2001	SCD-r1	440		0.00		1.2¶¶	Yang et al. (2009)
China (N)	Gaoyang§§	2001	SCD-r1	540	0.00	0.04			Zhang et al. (2012b)
China (N)	Gaoyang	2001	GYBT	560		0.24		1.4§§	Xu et al. (2005)
China (N)	Langfang	2000	LFR10	250***				1.0***	Luo et al. (2007)
China (N)	Qiuxian	2011	QX7	460	1.0	0.83	0.97	4.2	This paper
China (N)	Xiajin	2009	XJ-r15	140	0.65	0.68		1.4	Zhang et al. (2012b)
China (N)	Xinxiang	1996	BtR	3000***		0.28		1.1***	Luo et al. (2007), ¶ Liang et al. (2008)
China (NW)	Shache	2010	SC23	39	0.00				Zhang et al. (2012a)
China (NW)	Shawan	2010	SW34	31	0.26				Zhang et al. (2012a)
Australia	Mixed†††		BX	260		0.39	0.00, 0.63‡‡‡	1.4	Akhurst et al. (2003), Bird and Akhurst (2004, 2005)
India	Akola		Cry1Ac- resistant	72				1.1	Rajagopal et al. (2009)
India	Gujarat	2002	Res-Bt	93		0.42	0.43		Kranthi et al. (2006)
India	Gujarat	2006	BH-R	230		0.85§§§			Nair et al. (2010)
India	Nagpur	2002	Res-Ac	210		0.56			Kranthi et al. (2006)
India	Punjab	2005	BM-R	72	0.00¶¶¶	0.31			Kaur and Dilawari (2011)
India	Tamil Nadu		BCR	13		0.37			Shanmugam et al. (2007)
Pakistan	Punjab	2010	Cry1Ac- SEL	5400****		0.59			Alvi et al. (2012)

^*N indicates northern China; NW indicates areas of northwestern China with limited planting of Bt cotton.

^†The year when insects were sampled from the field to start the strain.

^‡Resistance ratio, LC₅₀ of Cry1Ac for the resistant strain divided by LC₅₀ of Cry1Ac for a susceptible strain.

^§Inheritance was autosomal in all strains except BH-R; when h was reported for each reciprocal cross, the mean is shown.

^¶h calculated from survival at a diagnostic concentration (1 μg Cry1Ac/cm² diet unless noted otherwise; see Methods).

^**h calculated from LC₅₀ values of Cry1Ac (see Methods).

^††h calculated from survival on Bt cotton leaves unless noted otherwise (see Methods).

^‡‡Cross-resistance ratio; LC₅₀ of Cry2Ab for the resistant strain divided by LC₅₀ of Cry2Ab for a susceptible strain.

^§§The r₁ allele from GYBT was introduced by repeated crossing and selection into the susceptible SCD strain.

^¶¶Based on Cry2Aa, which is similar to Cry2Ab.

^***Based on concentration of toxin causing 50% weight loss (WLC₅₀) of the resistant strain divided by WLC₅₀ of a susceptible strain.

^†††Created by pooling three strains, one from Queensland and two apparently from New South Wales.

^‡‡‡0.00 on young, intact plants; 0.63 on older, intact plants with a lower concentration of Cry1Ac.

^§§§0.97 for the cross with resistant females; 0.73 for the reciprocal cross (mean h = 0.85).

^¶¶¶Diagnostic concentration of 1 microgram Cry1Ac/mL diet.

^****Relative to the LAB-PK strain that was lab-selected for increased susceptibility.