Enhancing the Adaptation to Italian Environments of Egyptian Lucerne Germplasm for Exploitation as a Component of Free-hybrids

Free-hybrids between genetically-distant, well-complementing popula- tions have been proposed for enhancing heterosis in lucerne. Egyptian germplasm is a candidate component of free-hybrids in Italy, owing to its history of cultiva- tion in relatively isolated environments. However, exotic candidate components of free-hybrids need to undergo selection for local adaptation, which, for Egyptian germplasm, mainly concerns improving winter hardiness. Some 74 genotypes belonging to 17 Egyptian landraces and two Egyptian varieties which were devel- oped by preliminary selection across one winter in an open cold greenhouse, and 74 genotypes selected from a locally well-adapted Italian landrace, were evalu- ated in northern Italy as replicated clonal material for dry-matter yield, disease tolerance and survival after two winters under field conditions. On average, the exotic germplasm displayed distinctly lower disease tolerance and final survival than the Italian germplasm, while showing a non-significant trend towards lower yield. Egyptian variety germplasm was superior to Egyptian landrace material in all respects. Rare, outstanding Egyptian genotypes could be identified, which were used to synthesize a 10-parent synthetic population. However, further improvement of winter hardiness seems necessary to make this germplasm commercially usable for free-hybrids. Schemes for producing two-way or three-way free-hybrids from Egyptian, Italian and another foreign germplasm source are discussed.