DOI: 10.36347/sjavs.2015.v02i02.005

Pages: 102-107

The chemical insecticides have been the main method of pest control that is costly (30-40% of the total cost), polluting to the environment and damaging to the quality of life. The experiments were carried-out in Gedarif State at two site viz., North, South Gedarif and Damazin (Blue Nile State) during 2011/12 and 2012/13 seasons. Bollworms are the main pest inflecting major loss to the yield and constitute about 50% of the total insect control cost. The objective of this research was to evaluate two Chinese Bt cotton genotypes against the African bollworm, Helicoverpa armigera (Hubner) damage under rainfed conditions. Two Bt-cotton genotypes; a Seeni 1 (Chinese 1) and Seeni 2 (Chinese 2) cotton introduced by China-Aid Agricultural Technology Demonstrations Center for evaluation and release for commercial production in Sudan. The two genotypes carry Cry1A gene from Bacillus thuringiensis (Bt) which is specific toxin against Lepidoptera larvae to protect cotton crop against bollworms. Results obtained showed that the damage by the bollworms was significantly lower or negligible on the two Bt-genotypes compared to the local checks across the three sites and overall % bolls damage was 1% on the Bt genotypes CN-C01 and CN-C02 compared to 82 and 89 % on the two local checks Abdin and Hamid. The number of bolls per plant at harvest was significantly higher on the two Bt-genotypes (18 to 20) than the two local checks Abdin and Hamid. The seed cotton yield (SCY) was significantly higher in Damazin followed by South Gedarif and North Gedarif. The overall SCY of the Bt-genotypes CN-C01 and CN-C02 was 762 and 720 kg/ha, respectively, compared to 362 and 347 kg/ha for the two checks Abdin and Hamid, respectively. The GOT of the Bt-genotypes was significantly higher ranging between 42-44%, while that of the local checks ranged between 32-35%. The lint yield of the Bt-genotypes was 312 and 301 kg/ha while that of the local checks was 118 and 121, respectively. The lint yield of C