Jones' most influential contribution was the development of the double-cross hybrid method, which built on earlier work on heterosis by
George Harrison Shull and
Edward Murray East. While Shull and East had demonstrated that crosses between
inbred lines could produce vigorous hybrid offspring, the low seed yield of inbred lines made commercial production impractical. Jones solved this problem by crossing two single-cross hybrids derived from four inbred lines, producing a double-cross hybrid that combined high yield with sufficient seed production for large-scale agriculture. This innovation enabled the widespread adoption of hybrid maize in the United States during the 1920s and 1930s and became widely used in plant breeding. Jones' work helped establish hybrid breeding as a practical agricultural technology and complemented parallel advances by contemporaries including
Paul Mangelsdorf and other early maize geneticists. In addition to his work on hybridization, Jones conducted important studies on
inbreeding depression,
heterosis, and the genetic control of
endosperm development in maize, contributing to the development of plant genetics as an experimental discipline in the early twentieth century. ==Selected publications==