ABSTRACT

Recently-developed tools and techniques for molecular analysis of crop plant genomes offer new speed and efficiency to crop improvement programs, new information of unprecedented detail regarding genetic and evolutionary questions about crop plants, and the opportunity to exploit the vast potential of genetic engineering in crop improvement through "map-based" cloning of agriculturally important genes (1-2).

Cotton molecular genetics has recently made a major advance, by construction and application of a detailed RFLP map of the cotton chromosomes (3). These tools, together with new molecular tools for cloning large segments of cotton chromosomes (4), will make it possible to characterize agriculturally important genes in cotton with even greater efficacy than has been achieved in human genome mapping.

A molecular map of cotton can expedite many classical objectives in cotton improvement, and provides new tools for detailed re-evaluation of classical ideas about genetics and evolution of cotton. Ongoing investigations in my lab, in collaboration with numerous other groups. Include identification of genes associated with improved fiber quality, disease and insect resistance, and tolerance of environmental stresses, as well as characterization of historical and recent introgression into the gene pools of cultivated cottons, and analysis of evolutionary relationships across the Gossypium species complex.

It is important to note that it remains difficult to identify large numbers of DNA markers which distinguish among closely-related cottons, such as elite breeding lines front the same production region. This constraint can be overcome, and we are investigating improved methods for distinguishing between elite cotton cultivars.

Although several of the objectives mentioned above will yield first results soon, most are long-term undertakings which will be best accomplished through scientific interaction among investigators across the Cotton Belt. Like classical cotton improvement, molecular approaches to cotton improvement must accommodate inherent variations in environment across the Cotton Belt, as well as genetic fine-tuning of elite cultivars to meet needs of particular regions and markets. We look forward to working with the cotton community, toward the mutual objective of improving the quality, productivity, and utility of cotton.