Bidirectional Selection for Birdsfoot Trefoil‐Compatibility Traits in Orchardgrass

Abstract

Perennial grass‐legume mixtures are important in forage production, but little effort has been devoted to breeding either the grass or legume component for increased compatibility in mixtures. The objective of this research was to study response to selection for birds‐foot trefoil (Lotus corniculatus L.)‐compatibility traits in orchard‐grass (Dactylis glomerata L.). Six Cycle‐1 populations were developed by bidirectional selection in Iowa 79‐OGP‐DT for maturity, spring canopy height, and a compatibility index incorporating spring vigor, spring canopy height, growth habit, and tiller number. Significant direct and correlated responses were obtained from bidirectional selection for each trait or combination of traits. Selection for late maturity, short spring canopy height, and a low compatibility index value always increased days to anthesis and decreased spring canopy height, erectness of growth, tiller number, and dry‐matter yield in a space‐planted test, with the converse occurring from selection in the opposite direction. The three populations derived from selection for a low compatibility index value, short canopy height, and late maturity yielded less forage than their respective divergent populations in a space‐planted test, in dense monoculture stands, and in mixtures with birds‐foot trefoil. The lower‐yielding populations permitted significantly more birdsfoot trefoil production than the higher‐yielding populations in mixtures. This research indicates that it is possible to increase the compatibility of orchardgrass with birdsfoot trefoil by selecting among spaced plants for decreased spring canopy height, decreased tiller number, and delayed maturity.