Abstract: A method of biothermographically screening plants for favorable genetic characteristics such as drought resistance or heat tolerance is provided which comprises the nondestructive laboratory measurement of heat production of the plant sample or viable part thereof in a microcalorimeter under a given set of environmental conditions, and then using the measured heat production to assess the plant sample's potential reaction in the wild to those same conditions. The biothermographic analysis of the present invention represents a rapid, nondestructive way of predicting potential biological or economical yield under a variety of environmental field conditions, and can be conducted in a simple and inexpensive manner so as to particularly benefit those in the fields of agricultural biotechnology, plant genetics, and crop management.