Anther culture of Sorghum bicolor (L.) Moench

The sequence of pollen development from the tetrad stage to the mature tricellular grain was studied in freshly harvested anthers of Sorghum bicolor. This pattern of development was then compared with that occurring during panicle pretreatment and subsequent anther incubation in vitro. It was found that during pretreatment at 7° C mitoses of the vegetative cell were induced in up to 30% of the pollen. During anther incubation procallus development was highly polarised with contributions from both the generative and vegetative cells. After pretreatment at 14 or 20° C the generative cell became detached from the pollen wall and it was not possible to determine whether subsequent development involved only the vegetative cell or both the vegetative and generative cells.Although retarded pollen grains were observed both in vivo and in vitro, and were occasionally seen to divide in culture, they did not appear to be the source of the procalluses produced.     

Future prospects for transgenic crops

Transgenic (genetically modified) crops are grown at present on more than 40 million hectares in 13 countries around the world. These `first generation' products principally comprise soybean, maize (corn) and cotton resistant to herbicides and/or insects. This review considers the wide range of `second generation' products under development and testing in many commercial and academic laboratories. Such products include examples for a variety of food, medical, veterinary and industrial purposes. In addition the review assesses the present state of public acceptance of transgenic products.