A New Red Clover 2,4-D-Resistant Cultivar to Improve Broadleaf Weed Control and Elucidate the Molecular Mechanism of Resistance

摘要

Trifolium pratense L. (red clover) is an important forage legume worldwide, grown alone or in mixture with grasses, second only to Medicago sativa L. (alfalfa). It is a high-quality forage and very versatile as it can be grazed, harvested for green chop, made into hay, or lately also used in haylage. The University of Florida Forage Breeding Program has already released high-yielding nondormant cultivars (i.e., Cherokee) (Quesenberry et al. 1993), focusing on resistance to root-knot nematodes (i.e.,Southern Belle) (Quesenberry et al. 2005), and mid-dormant yield with RKN resistance (i.e., Barduro) (Quesenberry and Blount 2012). However, the establishment of red clover {Trifolium pratense L.) is still a challenge due to factors such as limited rainfall, warm temperatures, but mainly by competition from broad-leaf weeds due to its long seedling stage. While broad-leaf weed control in grasses can be accomplished inexpensively using herbicides like 2,4-Dichlorophenoxyacetic acid (2,4-D), no alternatives exist for red clover, as they are susceptible to this herbicide.