ISHS Acta Horticulturae 109: III International Symposium on Flower Bulbs
LEAF DEVELOPMENT, DRY-MATTER PRODUCTION AND BULB PRODUCTION OF SOME TULIP CULTIVARS |
| Author: | G.G.M. van der Valk |
| Abstract:
In field experiments the development and the performance of ten tulip cultivars, grown from four bulb sizes, were compared. In 1979, bulb weight (W) and the maximum leaf area (LAmax) were related as: LAmax = .00175 W + C. Values of C varied between .0040 and .0175 m2pl-1, depending on the cultivar. Cultivars also differed considerably in earliness of leaf development, in date of senescence and in duration of the growth period. In these respects bulb-size effects were negligible. Rates of dry matter increase, calculated from periodic harvests, were strongly correlated with the leaf area index. No evidence was found of any cultivar or bulb size effect besides the leaf area effect. Measured rates of dry-matter production agreed well with the rates of net photosynthesis calculated with De Wit's model for gross dry-matter production of leaf canopies, taking into account correlations for respiration losses and for partial soil cover, both derived from previous experiments. Assuming bulb dry weight equal to total dry matter increase during the growth period, and using .45 as the dry weight fraction of bulb weight harvested, bulb production could be calculated with good accuracy for all cultivars and bulb sizes. | |
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