Proc. EUCARPIA Symp. on Fruit Breed. and Genetics Eds M. Geibel, M. Fischer & C. Fischer Acta Hort. 538, ISHS 2000 775 NEW STRAWBERRY CULTIVARS AND PROMISING SELECTIONS FROM THE FRUIT RESEARCH INSTITUTE PITESTI, ROMANIA M.S. Coman, A.N. Popescu and V.S. Isac Fruit Research Institute 0300 Pitesti Romania Key words : Fragaria spp., breeding, interspecific hybridization, in vitro techniques, somaclonal selection Abstract As a consequence of the increasing interest for strawberry growing in Romania, a sustained strawberry breeding program is undergone at the Fruit Research Institute Pitesti, by using both conventional (intraspecific and interspecific hybridization) and unconventional methods (in vitro manipulation of the ploidy level, androgenesis, embryo rescue, somaclonal selection). Two recently released strawberry cultivars, named ‘RoReal’ and ‘Magic’, which were joining to ‘Premial’ and ‘Coral’, the other two Romanian strawberry cultivars, are among the notable results of this breeding program. These are short-day type and mid-season cultivars, of very good quality, with red stele tolerance, suitable especially for fresh market. A strong day-neutral selection (92.21.1), very attractive because of its regular conical shape and bright red colour, a somaclonal variant (ROP92.3.013) selected among the ‘Gorella’ plants regenerated from petiole-derived callus, having modified fruit pulp colour (white) and high sugar content, and a Fragaria vesca semperflorens selection (88- 10C7-14), with very vigorous plants and big elongated fruits, are among the other significant results obtained in recent years. Also, a very interesting range of interspecific hybrids was already obtained, which would allow consistent advances towards the introgression of useful genes from wild species of Fragaria into valuable synthetic strawberry genotypes. 1. Introduction The improvement of strawberry assortment, and particularly the obtention of well- adapted cultivars under specific environmental conditions, having a higher yielding potential, better fruit quality, and extending the fruiting season, is still a very important task for strawberry breeders in Romania. The germplasm fund available for reaching the objectives of the new program for strawberry improvement initiated since 1990, completed in recent years with very valuable sources of genes for characters of major importance, such as fruit size, yielding potential, disease resistance or tolerance, fruit quality, etc. (Coman et al., 1994), allowed a large range of hybrid combinations for the desired characters. About 50 crosses were yearly made using autochtonous lines and the most valuable donor genotypes for various traits, although the highest priority is given to fruit quality and productivity, and more than 7,000 seedlings were evaluated on average per year in advanced trials for their fruiting performance and adaptability to soil and climatic conditions of Romania. As the introgression of genes for disease resistance and high adaptability to less adequate environments from selections of wild species of Fragaria into cultivated strawberries, seems to be a way to obtain improved genotypes, interspecific hybridizations became an important component of the strategy followed to achieve such improvements. In vitro techniques, such as somaclonal selection, ploidy manipulation by colchicine treatments, androgenesis and rescue of potentially valuable genotypes originating from interspecific hybridizations by culturing immature zygotic