Colloquium, p. 445-468

Crop improvement is measured by new cultivars with improved yield, pest resistance, and/or product quality. It is not easy to develop a cultivar that is commercially successful for a long period of time. Of the many cultivars that are released, only a small percentage are successful as measured by large market share over a number of years. The difficulty involved in developing successful cultivars is probably underappreciated by many outside of plant breeding and even by some plant breeder/geneticists not engaged in finished cultivar development. This is an important point for those engaged in biotechnology. Engineered genes should be inserted into a successful cultivar in order to accurately define and maximize their impact. Historically, it is rare that the impact of a new cultivar is so great that existing cultivars are rendered obsolete and that newly available traits become a requirement of all future cultivars. Occasionally, a cultivar is released that is so good that it is grown on major acreages for decades, with a prime example being the ‘Russet Burbank’ potato. More often, improvements are of a minor nature and the successful new cultivar will be grown on lesser acreages and/or for a shorter time period before being replaced. However, most cultivar releases do not work out as planned and fail to be widely grown at all. Although these cultivar releases may have some improvements, they usually have an unanticipated weakness that limits their acceptance in the marketplace. Sometimes lack of acceptance is a marketing problem. Regardless, even unsuccessful releases were generally deemed worthy of release by their breeders and represent some of the best germplasm in a given breeding program. It can be concluded that developing a commercially successful cultivar is a difficult task that requires patience and hard work. The value of the background gene combinations required for a successful cultivar should not be underestimated by anyone who hopes to market a new improved cultivar by conventional breeding or a biotechnological approach. The term biotechnology is a broad term encompassing a wide range of science. For plant improvement it could include molecular markers linked to genes of interest or it could involve plant transformation. For this paper the focus will be on plant transformation where genes are modified or transferred by molecular means. Biotechnological advances hold promise as a means to solve problems that are intractable by traditional plant breeding methods and provide tools that are of potential benefit for crop improvement. With the above discussion on cultivars in mind, will the biotechnological improvements have major or minor impact? This depends on the improvements that are forthcoming and will need to be measured on a case-by-case basis, just as with new conventionally bred cultivars. Many in the scientific community certainly have been enamored with the promise of biotechnology. Whereas no one could dispute the tremendous advances in basic plant science that have been made possible by biotechnology, the impact is not as clear when it comes to plant improvement. Over the last two decades, there have been many claims made for biotechnological “silver bullets” that will revolutionize the kinds of cultivars that are grown for a given crop. Perhaps this is due to the expense of biotechnological research. Why invest large sums of money for a less than monumental improvement? Today, there is a better understanding of the interface between biotechnology and plant breeding. Unlike the 1980s, there are few that still believe that biotechnology will make plant breeders obsolete. 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