Does the “high sugar” trait of perennial ryegrass cultivars express under temperate climate conditions?

The objective was to evaluate water‐soluble carbohydrate ( WSC ) and crude protein ( CP ) concentration of perennial ryegrass ( PRG ) cultivars with different genetic potential for producing WSC under two contrasting agronomic managements in temperate climate (southern Chile). A 4 × 2 factorial design was randomly allocated to 24 plots (31 m 2 each, three blocks): four PRG cultivars (diploid standard cultivar, “2nSt”; tetraploid standard cultivar, “4nSt”; diploid high sugar cultivar developed in New Zealand, “2n HSNZ ”; and tetraploid high sugar cultivar developed in Europe, “4n HSEU ”) and two agronomic managements (“favourable,” defoliations at three leaves per tiller and nitrogen (N) fertilization rate of 83.3 kg N ha −1  year −1 ; “unfavourable,” defoliations at two leaves per tiller and N fertilization rate of 250 kg N ha −1  year −1 ). Herbage samples were collected in early spring, spring, summer and autumn. Concentration of WSC did not differ among cultivars in spring and summer, averaging 194 and 251 g/kg DM, respectively. The cultivar 4n HSEU had the greatest WSC concentration in early spring and autumn (187 and 266 g/kg DM , respectively) and the greatest CP concentration across samplings (average 230 g/kg DM ). Favourable management improved WSC concentrations in early spring and summer and decreased CP in spring, summer and autumn. Annual DM yield did not vary with cultivar or management, averaging 8.43 t/ha. Within a 12‐month study at one site in a temperate environment in southern Chile, PRG cultivars have not shown a consistent expression of the “high sugar” trait, where a genetic × environment interaction might be operating.