In the USA, the major proportion of maize and soybean production is from transgenic varieties produced for either insect resistance or herbicide resistance. These varieties have been consumed for more than 20 years now without any reported adverse effects. However, in other parts of the world there has been opposition to transgenic fresh food crops. Public concerns may moderate with time, as demands on crop productivity to feed a growing population increase, to cope with changing climatic conditions or pathogen pressures, or as fruit with distinct consumer benefits in flavour, eating quality or nutritional content are developed.
The virus-resistant papaya provides a dramatic example of how molecular techniques can enhance the properties of a crop in ways that can potentially help either productivity or postharvest handling and eating qualities. Political and ethical issues aside, wider use of genetically engineered plants could have a major impact on postharvest handling of many other horticultural products. Consumers will need to be well informed about changes resulting from conventional breeding and those resulting from genetic engineering or from mutations induced by chemical or irradiation treatment. There will also need to be improved physiological and biochemical knowledge about the postharvest responses of each species to be engineered.
Over the past century, fruit production and postharvest technology have been a powerful influence on progress in human societies and personal lifestyles. Very few people in ‘developed societies’ now grow their own fruit or vegetables; mass production has become much more efficient and wastage much lower; food quality has increased and people are better nourished; seasonal fruit are available year round; large amounts of product are distributed worldwide. Even cut flowers have become commodities of global trade instead of specimens from our own gardens, and in all cases postharvest technology has grown from process physiology. This area of plant science still offers exciting prospects for global horticulture, especially in tropical environments where new issues confront physiologists.