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Brittlenes of thie stem was found to be one of the more frequently segregating traits in inbred rye lines. In dependenece on the outset cultivated variety this trait appears in the S₂ generation in 4.0-0.6 per cent of the inbred lines. Genetical analysis demonstrated that the trait of brttlenes is determined by one recessive gene denoted by the symbol b_s (brittlee stem). The bs gene exerts a strong pleliotropic effect on the whole plant, beside brittleness of the stem it causes fragility of the roots, heads and leaves and depresses the general viability of the plants. Anatomilcal observations of thie stem and root sholwed that the b_s gene causes disturbances in the norirmal lignifcation of the sclerenichyma cells both in shoots and roots, so that these cells are th1i-walled. The tickness of the sclerenchyma layers and the number and size of the vasclcuar in the brittle forms are significantly smaller than in the normal ones. It was found that these changes appear in the bittle forms at the phase of heading of the plants.

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Globular 32 and 64 celled embryoids were obtained from uninucleate apple microspores (cultivar Jonathan) after 5 weeks of culture on a modified Murashige and Skoog (1962) medium. A similar induction of microspore development was not observed in younger or older stages of anther development. In such anthers only callus was formed from diploid tissues.