Breeding radish for winter production under glas

1. When radish is grown during the winter in cold glasshouses it frequently happens that no full grown fleshy roots are formed but bolters. This investigation is concerned with the factors which are most important in controlling the development of the radish plant, and with the cause of this lack of root thickening. 2. It appeared that an annual radish plant will ultimately bolt under any normal set of conditions, but that the rate of bolting is increased by high temperature and a long photoperiod. 3. 3.Root thickening is possible only if the planting distances are not too narrow and if there is enough light in relation to the temperature. 4. From a cultural standpoint the remedy is: give the plants enough space, keep the temperature down, and utilize the available light. 5. To breed plants more adapted to the unfavourable conditions, they should be grown and selected under conditions of rather high temperature and relatively low light intensity.