Progenies of the crosses of tetraploids and diploid FDR (First Division Restitution) clones were compared for true potato seed cultivation methods. Correlations were not observed for the tuber production between true potato seed and tuber cultivation methods. True seed obtained by open pollination of tetraploid clones and F1 seeds obtained by crosses of tetraploid x FDR clones were cultivated in fall and spring. Total tuber production were higher in fall or in spring on the parents, however, marketable tubers (above 50 grams) were produced more in fall than in spring in all lines. Cross pollinated F1 progenies were superior in the tuber production than the open pollinated progenies. This indicated that heterosis by genetic diversity was important in the true potato seed production

For one crucial century in the sequence of history, technology and economics created the unique opportunity to unfold their tricks without taking biology seriously into account. This might, in the long run, turn out to be mankind's greatest and most fateful mistake (2). According to Zadoks and Koster (53) the discipline of plant pathology originated during the potato blight of the nineteenth century. In a sense, the discipline was born in the context of technical changes that were incorporated into agricultural practices and thought to be unequivocally positive in their impacts. Yet, as Butler has recognized, the "side-effects of breedings for agronomic features desirable in themselves are well known as the "Green Revolution" (53). Adopting a systems perspective in selection of crop varieties would have made it possible to anticipate many of these secondary impacts. Perhaps the blight problem in Europe was a precursor of things to come. Inadequate attention to basic ecological interactions occurring and changing within a system results in "surprises" that require attention. However, if the attention is given in the strict disciplinary sense, it is quite possible that it will be directed specifically to correcting rather than understanding the totality of the problem being addressed. This has been the lesson of the "green revolution". The commonplace statement that everything is connected to everything else must be understood in its entirety today more than at any time in history. The flexibility with which modern agriculture has to respond to specific needs is more narrow tahn ever before. Much of the diversity that historically characterized the ecological systems that have supported human food production activities has been driven out. Mistakes are often not self-correcting and can easily compound the problem. In this context, the challenge to the plant protection disciplines is not necessarily to adequately respond to specific trangressions, whatever their source; rather, they must understand and document, in a broader context, the evolving system characteristics that will bound and delineate the more specific responses. Genetic engineering might produce dramatic gains in the direct response to specific maladies. Yet, if such engineering is undertaken with little or no understanding at the system level, it merely becomes a "band-aid" approach to the problem. The seemingly inevitable increase in the human population will require increased attention to global food production and distribution. If we focus on increased production, without understanding the indirect and subtle ramifications of the techniques employed in raising production, we will run the unthinkable risk of facilitating population growth in the short-run that we will be unable to maintain in the long-run. This would result in a veritable cul de sac for the world. From 1850 to 1925 plant pathology has focused on the fungus, the host, and environmental interaction, respectively (53). More recently, plant pathology, and more generally, the plant protection disciplines, have concentrated their efforts on integrated management or plant protection. This concentration implicitly recognize the failure of post World War II synthetic chemicals to achieve long-term stability in agricultural production. In many respects, this system sacrificed ecological stability for maximum yields, a trade-off we are beginning to seriously question