Published online by Cambridge University Press: 27 March 2009
Evidence is presented that, in Italian ryegrass, the ability to survive in the sward into a second year after sowing may be assessed on spaced plants or on closely planted rows. There is no indication that selection for the ability to survive into the second year need cause loss of yield in the first year after sowing. In an earlier paper based on the same experiment (England, 1975) incorrect formulae were used for calculating family heritabilities and genetic correlations. In an appendix the correct formulae are derived and the consequent changes in the conclusions of the previous paper are described.