Physiological Basis of Yield and Environmental Adaptation in Cotton

In the early part of the biotechnology era, great expectations were placed on the potential to modify major biochemical pathways and physiological parameters of crops, e.g., creation of nitrogen-fixing corn. Thus far, that expectation has not materialized. As our knowledge of plant metabolic and molecular systems responsible for physiological function have grown, so too has the awareness that those systems are highly integrated and not easily modified by simple approaches. In cotton, as in most crops, genetic yield parameters are multigenic and rarely susceptible to modification through genetic engineering with one or two genes. To provide the reader a realistic background to the application of biotechnology to cotton yield improvement, the physiological aspects of yield development and adaptation to environmental stresses are emphasized in this chapter. Where appropriate, potential applications of biotechnology and/or molecular techniques to enhance yield components are discussed.