Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 19, 1996
Publication Date: N/A
Interpretive Summary: Most red clover cultivars are bred for grazing or for frequently clipping for hay and silage. An important factor for successful red clover forage production and utilization is the ability of the plants to persist for more than one season. Improved cultivars are able to persist longer and yield more than common cultivars under disease pressure in forage growing states such as Wisconsin. This results in greater sustainable forage production. However, these superior yielding cultivars have a low seed yielding potential so many seed producers in the western states prefer to grows the higher yielding common ecotypes that are not good forage producers. This research showed that high forage producing cultivars are more disease resistant than common ecotypes, but are poor seed producers. It was also shown that selection for disease resistance in Wisconsin increased forage yield but did not benefit seed production in Oregon because different root rot diseases existed in the two regions. It was found that the seed yielding capacity of the varieties examined was highly associated with the number of flowers produced by late July. Using this finding, it was determined that the greatest improvement in seed yield capacity of high forage yielding cultivars could be made by selecting for rapid flowering after spring forage removal in the western Oregon seed production region.
Technical Abstract: Red clover (Trifolium pratense L. is an important forage legume growing in the USA, Canada and northern and eastern Europe. Environmental stresses and root rot diseases contribute to a general lack of persistence in Wisconsin forage production systems. However, the benefits of selection for improved forage persistence in Wisconsin on seed production in Oregon are unknown. The effects of root rot resistance of six improved cultivars and three regionally adapted ecotypes on forage and seed yield under typical production systems in Wisconsin and Oregon were measured. The relationship of cultivar flowering capacity with seed yield as also measured. The objectives of this study were to: (i) determine the benefits for using improved cultivars instead of locally adapted ecotypes in Wisconsin forage production systems; (ii) determine whether selection for root rot resistance in Wisconsin benefits seed production systems in Oregon; and (iii) identify strategies to increase seed yields in cultivars with improved persistence and high forage yields. Forage and seed yields were inversely related in all improved cultivars and equal to the three local Wisconsin and Oregon ecotypes. The local ecotypes were the highest seed yielding entries. Root rot resistance in Wisconsin had no benefit for seed production in Oregon. Seed yield was highly associated with the number of flowers produced by late July (r=0.87; P< 0.0002). Improvement in seed yield capacity of cultivars with high forage yield may be possible from selection for rapid flowering after spring forage removal in the western Oregon seed production region.