Yield stability of Festulolium and perennial ryegrass in southern and central Sweden

This study investigated yield stability over three years of Festulolium species and perennial ryegrass (Lolium perenne L.) under the agro-ecological conditions of southern and central Sweden using 26 trials from the official variety testing of forage crops in these regions in the period 2006-2010. The first harvest in each year was used as a measurement of yield stability. In southern Sweden, the decline in dry matter yield at first harvest (DMYFH) over the three years was largest in perennial ryegrass, but significantly less in loloid Festulolium. Yield of festucoid Festulolium did not decrease and had a significantly different (P < 0.001) slope coefficient to the other species. In central Sweden, there were no significant differences in DMYFH between varieties and species in the third year, but festucoid Festulolium suffered significantly less yield decline than the other two species. The Festulolium varieties behaved differently between the two regions, mainly because of greater winter damage with increasing latitude. Perennial ryegrass displayed similar behaviour in both regions.