1983 Volume 52 Issue 3 Pages 308-315
The present study was undertaken to make clear the effects of plant density on the growth and quality of cut flowers in early-forced tulips. The cultivars used were‘Cassini’and‘Apeldoorn’in 1979 and‘Cassini’, ‘Trance’and‘Apeldoorn’in 1980.
1. The solar radiation in the plant community increased with decreasing plant densities. However, the effect of solar radiation on the areal weight, one of the determinants of cut flower quality, was not clearly recognized.
2. The dry matter production at the high plant density was larger at the early and middle growth stages but smaller at the late stage as compared with those at the control and low plant densities in‘Cassini’. While, in‘Apeldoorn’, it was larger only at the early growth stage and become smaller thereafter than those at the control and low plant densities.
3. The values of LAI increased with increasing plant densities and it was especially true of‘Cassini’. They were nearly proportional to the values of plant density (number of bulbs per unit area) in‘Cassini’ but not in‘Apeldoorn’.
4. The values of CGR also increased with increasing plant densities almost throughout the forcing period and it was especially ture of‘Cassini’. In‘Apeldoorn’, however, they increased slowly till the middle growth stage and increased rapidly thereafter.
5. In‘Apeldoorn’, the quality of cut flowers lowered with increasing plant densities, while in‘Cassini’ and‘Trance’ it was not affected by plant density. The ratio of dry weight of flower to that of a whole plant did not differ with plant density regardless of cultivars. However, the ratios of dry weight of stem and leaves to that of a whole plant increased and decreased, respectively, with increasing plant densities.
6. These results suggest that‘Cassini’and‘Trance’ can be forced at plant densities higher than usual without lowering flower quality, while for‘Apeldoorn’ plant densities higher than usual are not desirable.