Estimates of variance components and repeatability for total forage yield in rye: implications for breeding

摘要

Cereal rye (Secale cereale L.) is an important forage crop in the USA for stocker cattle (Bos sp.) production, thus making forage yield an important breeding objective for the crop. However, little information is known about the repeatability for forage yield in this crop. The objectives of this research were to: (i) estimate variance components for forage yield from long-term variety trials, (ii) estimate the repeatability for forage yield and (iii) relate this to breeding strategies for increased forage yield in rye. Trials were conducted over 14years where 97 USA open-pollinated varieties (OPVs) were evaluated. Repeatability ranged from 0.57 to 0.86 when the data were analysed by year for the 3years with significant genotype main effects. Possible explanations for the lack of significant genotype main effects are discussed. Practical implications of these findings indicate that the development of improved cultivars with greater forage yield will require improved methods of selection based on family performance rather than the current methods based primarily on single plant visual selection.