PLANT UNIFORMITY AT HARVEST RELATED TO VARIATION BETWEEN EMERGING SEEDLINGS

The variation of plant size at harvest affects the marketable yield of many vegetable crops.
This variation can be related to the size and time of emergence of the seedlings assuming simple ‘logistic’ growth and taking into account the effects of inter-plant competition.
The results expected from such a relationship compare favourably with observations on lettuces where 60–90% of the variation of harvested head weight was caused by variation in the date of seedling emergence.
The relationship also compares well with carrot observations where one third of the variation in harvested plant weight was caused by competition effects and two thirds by variation in seedling weights; uniform spacing having almost no beneficial effect on the uniformity of root size.
The available techniques for minimizing plant size variation are summarized and the beneficial effects of fluid drilling pre-germinated lettuce seeds are illustrated.

Symposium on the Timing of Field vegetable Production

I.E. Currah

https://doi.org/10.17660/ActaHortic.1978.72.6