Cross compatibility of cultivars of Gossypium hirsutum L. and feral Gossypium barbadense L. in the Southern Highlands of Tanzania

摘要

Cotton is the second most important cash crop contributing about 15% to the annual foreign earning in Tanzania and is purely from?Gossypium hirsutum?L. cultivars.?Gossypium barbadense?L., a textile source in other parts of the world occurs as a feral perennial of ornamental and medicinal value in home gardens.?G. barbadense?L. is a natural host of the red bollworm, a destructive pest to cotton. The Southern Highlands (SH) of Tanzania have been quarantined from cotton production to control spread of the red bollworm to other growing areas. Transgenic cotton expressing the delta-endotoxin genes from?Bacillus thuringiensis(Bt) offers an alternative control to the pest and reduced dependence on insecticide. Gene flow between wild or valued feral relatives and transgenic crops is?a biosafety?concern should transgene escape result in resistance development and contamination of germplasm. Potential gene flow between feral?G. barbadense(including?accessions?Gb1?and?Gb2) from the SH and?G. hirsutum?cultivars was assessed using controlled hybridization. The crosses produced fertile F1 but intraspecific seeds from?G. barbadense?did not germinate.G. barbadense?is more likely to receive than donate genes implying development of pest resistance?if introgressed?filial generations express the Bt product.