Factors infl uencing somatic embryogenesis and regeneration ability in somatic tissue culture of spring and winter rye

Rye is an important crop in Northern and Eastern Europe. However, the application of various biotechnologies in rye breeding has been limited duo to its recalcitrant in tissue culture. In order to improve somatic tissue effi ciency, key factors affecting somatic embryogenesis and reproducible green plant regeneration of rye (Secale cereale L.) were evaluated and optimised. In this study, a total 27 rye genotypes including 10 spring and 17 winter genotypes were involved in the investigation. Genotype, culture medium, sugar, gel agent and auxin infl uenced somatic embryogenesis of immature embryo signifi cantly. One-two weeks cold pretreatment of young embryo enhanced somatic embryogenesis and green plant regeneration. In culture of immature embryos, infl orescences and leaf segments of the seedlings, explants signifi cantly infl uenced the culture effi ciency. Highest embryogenic callus yield resulted from rye immature embryo as explant compared to young infl orescence and leaf segment of seedling. Developmental stage of embryo played an important role in somatic embryogenesis. Late spherical coleoptile stage (embryo size 0.5–1mm in length) was optimal developmental stage of immature embryo for culture. Morphogenetic potential of embryogenic callus decreased with an increasing number of subcultures, and this ability could be maintained in vitro for a maximum of 8 months of culturing.