ABSTRACT
The data presented in Figure 1 suggests a possible factor which may in the future exacerbate production losses. Presently, the increase in world population has exceeded the rate of increase in total cultivated land. Be tween 1961 and 1995, the amount of cultivated land has decreased from approximately 1.5 ha/person to 0.75 ha/person [2]. This increases the pressure to continually improve yields on a global scale. Attempts to real ize these increases involve the use of superior varieties, improved cultiva-
tion techniques, and increasing the area under cultivation. The latter fac tor often results in plants being grown in environments that are at the limit of the plants’ adaptive abilities. Increased exposure of plants to ad verse abiotic factors, such as drought and cold, is often a consequence of cultivation in marginal environments.
