ISHS Acta Horticulturae 109: III International Symposium on Flower Bulbs
METHODS OF SELECTION IN TULIP BREEDING |
| Authors: | J.P. van Eijk, W. Eikelboom |
| Abstract:
The long juvenile period and slow propagation of tulips are serious drawbacks in breeding. The Institute's research programme is therefore aimed primarily at the development of efficient methods of selection for such characteristics as bulb production, forcing ability, keeping quality and disease resistance. Comparison of the behaviour of small (juvenile)bulblets of well-known cultivars with that of large(adult)bulbs of the same cultivars has yielded criteria for early selction in seedling populations. For bulb production, annual increase of main bulb diameter and offset number during the juvenile period, proved to be effective preselection criteria. For a series of well-known cultivars, date of emergence, sprout development and brown colouring of bulb skin of juvenile bulblets at the harvest time were significantly correlated with flowering time of adult bulbs of the same cultivars in the field. It will be tested whether such correlations also exist in seedling populations. For selection on keeping quality, such characters as the dates of start of discoloration, of 50% discoloration and of perianth drop appeared to be useful criteria. The breeding values of a range of parents for keeping quality characters were determined on the basis of a diallel series of crosses. Juvenile and adult bulbs of the same cultivars showed good agreement in degree of resistance to Fusarium. Resistance of young seedlings is governed primarily by additive gene action. The GCA of individual parents generally corresponds with their phenotypic behaviour. | |
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