Outcrossing of non-Bt cotton (Gossypium hirsutum (L.)) in refuges by transgenic Bt cultivars could reduce the efficacy of refuges for delaying resistance in seed-feeding pests. Based on reports that outcrossing decreased as distance from Bt cotton increased in small-scale studies, we hypothesized that increasing refuge width or distance from Bt fields would reduce outcrossing. In a large-scale ...

Twenty-five years ago, the concept of using Agrobacterium tumefaciens (soil gm-ve bacterium) as a vector to create transgenic plants (natural transformation) was viewed as a prospect and a “wish.” Transgenic plants generated by direct DNA transfer methods (e.g., polyethylene glycol or liposome-mediated transformation, electroporation, or particle bombardment) often integrate a large number of c...

Background: A highly efficient genetic transformation system is essential for a successful genetic manipulation of the African violet (Saintpaulia ionantha Wendl.). Objectives: Developing a particle bombardment-based genetic transformation system for the African violet. Materials and Methods: A local cultivar of the African violet from Guilan province was used for transformation experiments. Th...

Verticillium wilt, caused by the Verticillium dahliae phytopathogen, is a devastating disease affecting many economically important crops. A receptor-like protein (RLP) gene, Ve1, has been reported to confer resistance to V. dahliae in tomato plants, but few genes have been found to be involved in cotton Verticillium wilt resistance. Here, we cloned two RLP gene homologs, Gossypium barbadense r...

The impact of multiple-year (0–5 years) cultivation of transgenic Bacillus thuringiensis (Bt) cotton on the functional bacterial populations in rhizosphere soil was investigated. The transgenic Bt ? CpTI cotton line SGK321 and a non-Bt cotton line Shiyuan321 were planted in four fields in which Bt cotton had been continuously cultivated for 0, 1, 3, and 5 years. Rhizosphere soil samples were co...

Several isolates of Bacillus thuringiensis (Bt) were screened for the vegetative insecticidal protein (Vip) effective against sap-sucking insect pests. Screening results were based on LC(50) values against cotton aphid (Aphis gossypii), one of the dangerous pests of various crop plants including cotton. Among the isolates, the Bt#BREF24 showed promising results, and upon purification the aphidi...

In Australia, the cotton bollworm, Helicoverpa armigera, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the Bacillus thuringiensis toxin Cry1Ac) has been grown for H. armigera control since 1996. It is demonstrated here that a population of Australian H. armigera has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant H. armigera ...

originally found in Mississippi in 1980 and by 2002 was estimated to infest 32.4% of the cotton hectarage in Cotton (Gossypium hirsutum L.) lint yields have not changed apMississippi (Lawrence et al., 2002). Although genetics preciably during the last decade. Because more and higher infestations is still probably the predominant reason for the lack of of reniform nematodes (Rotylenchulus renifo...