THE EFFECTS OF PLANT DENSITY ON ONIONS ESTABLISHED FROM MULTISEEDED TRANSPLANTS

An experiment was conducted to observe the effects of plant competition on the growth of onions in the initial plant raising stage and subsequently in the field following transplanting.
Seeds of cv.
Hygro and cv.
Hyfast were sown in multi-celled modular seed trays to provide four plant populations of 1,2,4 and 6 seedlings per cell.
These were grown under glasshouse conditions for 10 weeks before planting the individual cluster of seedlings in the field at a 10 x 10cm spacing to give final plant populations of 100, 200, 400 and 600 plants m^-2.

Plant competition during the seedling raising stage significantly reduced leaf number and plant dry weights and the observed differences were maintained during the subsequent growth period in the field.
At harvest there was a significant effect of planting density on individual bulb size but not on yield per unit area.
There was no evidence for differences between the two cultivars.

Leaf anatomy was affected by the treatments, with leaves from the lower plant densities being thicker and have larger cells.
The proportion of bulb scale to bladed leaf tissue in bulbs increased and bulb maturity as indicated by leaf fall over, was advanced by increasing plant density.

VII International Symposium on Timing Field Production of Vegetables

S.S. Weerasinghe, R. Fordham

https://doi.org/10.17660/ActaHortic.1994.371.11