RECURRENT RESTRICTED PHENOTYPIC SELECTION FOR FORAGE YIELD IN TIMOTHYAND ORCHARDGRASS

Three cycles of recurrent restricted phenotypic selection for forage y ield were carried out in orchardgrass (Dactylis glomerata L. 'Avon' an d 'Pennlate') and timothy (Phleum pratense L. 'Salvo' and 'Drummond'). The objectives of this study were to measure the effectiveness of thi s selection and to assess whether the selection produced any correlate d responses on other characters. The three selected cycles and the ori ginal populations (cycle 0) were evaluated in both sward and space-pla nted experiments over a period of 4 yr. For the majority of the years of evaluation, there were no significant (P < 0.05) differences in for age yield among the different selection cycles. Under space-planted ev aluation, cycle 3 of Drummond timothy was lower in both forage and see d yield than the other populations. In general, there was a trend to t aller plants with greater circumferences in orchardgrass, and shorter, smaller plants in timothy over selection cycles. Selection had little effect on plant persistence and maturity. In conclusion, three cycles of recurrent restricted phenotypic selection were not effective in im proving the forage yield of timothy or orchardgrass.