C-banding patterns were analysed in 19 different accessions of Aegilops caudata (= Ae. markgrafii, = Triticum dichasians) (2n = 14, genomically CC) from Turkey, Greece and the USSR, and a generalized C-banded karyotype was established. Chromosome specific C-bands are present in all C-genome chromosomes, allowing the identification of each of the seven chromosome pairs. While only minor variations in the C-banding pattern was observed within the accessions, a large amount of polymorphic variation was found between different accessions. C-banding analysis was carried out to identify Ae. caudata chromosomes in the amphiploid Triticum aestivum cv 'Alcedo' - Ae. caudata and in six derived chromosome addition lines. The results show that the amphiploid carries the complete Ae. Caudate chromosome complement and that the addition lines I, II, III, IV, V and VIII carry the Ae. caudata chromosome pairs B, C, D, F, E and G, respectively. One of the two SAT chromosome pairs (A) is missing from the set. C-banding patterns of the added Ae. caudata chromosomes are identical to those present in the ancestor species, indicating that these chromosomes are not structurally rearranged. The results are discussed with respect to the homoeologous relationships of the Ae. caudata chromosomes.

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The effect of genotype by environment interaction (G × E) was studied in marjoram in an experiment using 34 genotypes and three locations. For yield, no significant G × E was found, while for plant height, flowering time and the essential oil content, the G × E was significant. As to leaf colour, which was determined using the L*a*b* system and a sensorial score, only the coordinate a* was not significant. Both sensorial evaluations for smell and taste revealed some genotypes to be more stable than others. Regarding the essential oil compounds, both of the 'marjoramy' compounds, cis-sabinene hydrate and cis-sabinene hydrate acetate, were extremely unstable in one hybrid combination which, however, turned out to be the most stable comparing to the total amount of these two compounds. The main sesquiterpenes, β-caryophyllene and bicyclogermacrene, were strongly correlated in their stability, except in one case, where only bicyclogermacrene was highly unstable. The estimation of G × E allows the extrapolation of the degree of instability that is to be expected for a special trait. But, above all, when G × E is given special consideration, it is possible to select for stable genotypes that can be cultivated, e.g. in different regions with the resulting raw material being of higher homogeneity and the environmental influences minimised.

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