Recurrent restricted phenotypic selection for forage yield in timothy and orchardgrass

Abstract

Three cycles of recurrent restricted phenotypic selection for forage yield were carried out in orchardgrass (Dactylis glomerata L. 'Avon' and 'Pennlate') and timothy (Phleum pratense L. 'Salvo' and 'Drummond'). The objectives of this study were to measure the effectiveness of this selection and to assess whether the selection produced any correlated responses on other characters. The three selected cycles and the original populations (cycle 0) were evaluated in both sward and space-planted experiments over a period of 4 yr. For the majority of the years of evaluation, there were no significant (P < 0.05) differences in forage yield among the different selection cycles. Under space-planted evaluation, cycle 3 of Drummond timothy was lower in both forage and seed yield than the other populations. In general, there was a trend to taller 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 improving the forage yield of timothy or orchardgrass. Key words: Timothy, Phleum pratense, orchardgrass, Dactylis glomerata, recurrent selection