Intra‐ and Intervariety Crosses of <i>Medicago sativa</i> L. and <i>Medicago falcata</i> L.¹

Abstract

Interspecific, intervariety, and intravariety crosses in alfalfa were compared for expression of heterosis. In spaced plantings, highest yields were obtained from interspecific crosses, followed by inter‐variety and finally by intravariety crosses. Variability within progenies was increased through hybridization, unrelated parents having the most effect. The importance of genetic diversity in parents as a determinero f heterosis is considered.