ADVANTAGES AND LIMITATIONS OF USING IDEOTYPES TO BREED CROP PLANTS

Abstract

Most breeding programs uses grain yield as the main selection criterium to improve the agronomic performance of crop varieties. An alternative approach to improve productivity is the ideotype breeding. According to this philosophy, breeders should define an ideal plant type for a specific environment and then breed for this ideotype. Breeding through crop ideotypes is positive in terms of integrating principies of physiology, ecology and plant breeding, encoraging the generation of hypothesis about how yield is achieved and providing a holistic view about production systems. Ideotype breeding also presents some problems, such as the difficulty of identifying individual traits that enhance yield universally, abscence of adequate genetic variability for potentially yield enhancing traits and the need to select simultaneously for many characters rather than just for yield, increasing the size of lhe segregating population to evaluate. The major benefits of ideotype breeding have been expressed at a conceptual and analytical levei rather than in immediate direct yield improvements.