Response to Divergent Selection for Anthesis Date in Tall Fescue
Date of anthesis is the major factor controlling the seasonal distribution of forage yield and quality in tall fescue (Festuca arundinacea Schreb.). The objective of this experiment was to evaluate the response to divergent selection for anthesis date in three cultivars of tall fescue that differ for date of anthesis. Three cultivars, Fawn, Alta, and Kentucky 31, were evaluated for date of anthesis in the field from 1981 to 1983. There was a strong juvenile requirement for some genotypes within each cultivar; however, this tended to be more of a problem with the earlier-maturing cultivars, Fawn and Alta. Correlations of establishment year data (1981) with mature plant data (1982 and 1983) were low; consequently, establishment year data were not utilized in selecting for anthesis date. Selections for both earlier and later anthesis were made within each population based on mature plant data. The six selected populations and the three unselected parent populations were evaluated as mature plants in the field for 2 yr. All populations exhibited a significant response to selection except for the Fawn population that was selected for earlier anthesis date. Realized heritabilities for later anthesis were higher (0.71–0.79) than for earlier anthesis (0.18–0.38) within each cultivar. The variance for anthesis date within each cultivar was increased by selection for later anthesis and decreased by selection for earlier anthesis. There appeared to be sufficient residual variation for further selection in all populations, with the possible exception of the Fawn population that was selected for earlier anthesis.
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