The research activities of Dr. K. F. Kostina, a well-known expert in fruit plants in Russia, are also familiar to the international scientific community. A State Prize Laureate and Doctor of Agricultural Sciences, she developed a classification of common apricot varieties and forms, based on their botanical and geographic features, identifying the Central Asian, Iranian-Caucasian, European, and Dzungar-Trans-Ili groups, thus contributing to the progress of Southern Russia’s horticulture. The Chinese group was added somewhat later. Over 48 apricot and 32 cherry plum cultivars, developed with Dr. Kostina’s participation, enabled the cultivation of these fruit trees in various regions. Klavdia F. Kostina promoted N. I. Vavilov’s approaches to the study of wild fruit plant species, which helped to expand the cultivated assortment and use their habitats as a source for selecting and exploiting the most promising genotypes in breeding practice. She worked on the methods suited for the expansion of apricot and cherry plum commercial plantations, all but nonexistent in Russia prior to the 1950s. Her active involvement in the Exhibition of Achievements of the National Economy (VDNKh) was recognized with numerous gold medal awards.