ÃÞ »¨ ѧ ±¨ Cotton Science 2010£¬22£¨4£©£º297-303
Frequency of Bt Resistance Alleles in Helicoverpa armigera Populations from the Yellow River Cotton-farming Region of China Abstract: In 2007 to 2009, we used genetic method of isofemale lines F1/F2 to detect the frequency of Bt resistance genes in Helicoverpa armigera populations which collected from Anyang County , Henan Province, Weixian County, Hebei Province and Wucheng County, Shandong Province. A conservative estimation was carried out and showed that the resistance gene frequencies to Cry 1Ac in Anyang County population were 0, 0.00090 and 0.00103 in 2007, 2008 and 2009, respectively. While in Wucheng County population, the resistance gene frequencies were 0.00086, 0.00097 and 0.00052 in 2007, 2008 and 2009, respectively. In Weixian County population we didn't detect resistance genes in 2007, 2008 or 2009. In Anyang County population, the relative average development rate (RADR) of cotton bollworm larvae in F1 test has increased significantly year by year. In Weixian County population, the RADR in F1 test has no significant change. In Wucheng County population, the RADR in F1 test showed an obvious induced tendency. In general, the field populations of H. armigera in Northern China have not evolved prominent resistance to Cry 1Ac , and their resistance frequency to Cry 1Ac is at a normal level. But the tolerance of Helicoverpa armigera to Cry 1Ac toxin tended to increase, and the early resistance detection and alarm system should be initiated in China as early as possible.
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