Effects of heterosis for yield and yield components obtained by crossing divergent alfalfa populations

When breeding alfalfa for yield performance, it is necessary to use high-yielding parents obtained by different breeding methods. The assumption at the onset of this research was that crossing highest-yielding domestic cultivars with divergent populations from geographically distant breeding centers could result in the expression of heterotic effects in their hybrids contributing to increased alfalfa yield. The objective of this study was to determine yield and yield components and heterotic effects in hybrid progenies obtained by crossing the domestic cultivars NS Banat ZMS II and NS Mediana ZMS V with the cultivars Pella, Dolichi and Hyliki from Greece, UMSS 2001 from Bolivia and Jogeva 118 from Estonia in two series. The field trial planted in 2006, included 13 F1 hybrids and 6 and 7 initial parents in both series. Heterotic effects for yields of forage and hay were observed in 4 combinations. The populations that exhibited heterosis in a set of crossings are recommended for use as parent components for development of high-yielding synthetic alfalfa cultivars.