This research was carried out to develop synthetic cultivar of alfalfa with high forage yield and high quality under Mediterranean environment of Turkey during 2002-2009. To ensure a broad range of genetic variability, different alfalfa entries including cultivars, introductions and bulked populations, collected from different sources, were used to establish source nursery. From the original source nursery 380 superior plants (genotypes) out of 7680 individuals were selected and cloned. Thirty-two selected plants from the clonal line nursery were cloned and transplanted to an isolated polycross seed production nursery and were allowed to intermate randomly. Seeds were harvested from all propagules within a clone, composited and sown in replicated progeny test plots. In the progeny plots 32 lines and two standard check cultivars (Mesa-Sirsa and Artal) were evaluated for dry matter yield (DMY), crude protein (CP) content, crude protein yield (CPY), acid detergent fibre (ADF), neutral detergent fibre (NDF) and estimated digestible dry matter yield (EDDMY) during the 2008 - 2009 growing seasons. According to average of two years progeny test results, there were significant differences among alfalfa lines and cultivars in terms of above all mentioned components. Mean DMY, CP content, CPY, ADF and NDF concentrations and EDDMY were 8184 kg ha(-1), 18.1%, 3271 kg ha(-1), 40.7%, 46.7% and 10,290 kg ha(-1), respectively. The results indicated that selection for most vigorous tall-growing plants during the selection phases generally increased DMY, CPY and EDDMY but slightly decreased digestibility and intake potentials. It was concluded that lines 31, 15, 2, 20, 16, 24, 17, 25, 23, 13, 30, 28, 32, 5, 10 and 18 showed good adaptation and performed well under Cukurova ecological conditions by producing more EDDMY and CPY. These genotypes were chosen as components for establishment of a high-yielding nondormant synthetic variety.