An experiment to determine the effect of temperature and photoperiod on Lupinus albus under controlled environmental conditions was carried out, using the three Lupinus albus genotypes ‘Tifwhite’, ‘Esta’ and ‘Kiev’, and three temperature (10/20, 18/28 and 20 °C continuously) and two photoperiod (8 and 16 h daylength) regimes, in all combinations. Half of the seeds were vernalized for 21 days at 4 °C to alleviate the obligate vernalization requirement of Tifwhite. Although Esta and Kiev do not have obligate vernalization requirements, they were influenced by this vernalization period. Observations included the duration of the period from planting to seedling emergence, the duration of the period from planting to the beginning of flowering and the duration of flowering. The vernalization treatment accelerated plant development in all genotypes. The period from planting to emergence was shorter under the higher temperature regime. For all genotypes, the period from planting to flowering was shorter under the longer photoperiod, the same trend as would be expected for long‐day plants. Duration of flowering periods were, in contrast to pre‐flowering periods, shorter for all genotypes at cooler temperatures. The results of this study confirm that photoperiod does contribute to the growth period from planting to flowering in L. albus and that this species does behave as a long‐day plant.

The karyotype of Cyphomand'ra betacea SENDT. is described.

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Mitotic cycle time was estimated by means of a "natural method" in control and irradiated material of a dwarf tomato line in order to express the intensity of somatic selection in terms of this biological factor. In the "natural method" the mitotic index is estimated in relation to the number of hours after germination. The time interval between successive peaks in the mitotic index is considered to be an indication of mitotic cycle time. In control material mitotic cycle time was also estimated by the continuous colchicine method and compared with the "natural method".

The percentage of abnormal anaphases was determined in rooted leaf and stem cuttings from irradiated diploid and tetraploid tomato plants. It was confirmed that somatic selection is very fast but that even drastic abnormalities, giving rise to abnormal anaphases, seem to be stabilised at a low frequency. Little difference was found between diploid and tetraploid lines or between different genotypes. A considerable part of the anaphase abnormalities found are considered to have arisen de novo.