Abstract
100 unselected clones of sweet potato were grown on an acid, poorly drained soil (Cialitos clay, an Ultisol) in Puerto Rico, and in small pots where they were subjected to four kinds of stress; low fertility, acidity, root flooding and shade. Results of stress tests for soil of low fertility, for acidity, for shade tolerance but not for root flooding were correlated with yields in the field. Results of a single stress test or of combinations of tests could have been used to select most of the top yielding clones, but a few top clones showed no tolerance to the glasshouse-imposed tests.