EFFECT OF VARIATION IN TIME OF EMERGENCE OF BROCCOLI SEEDLINGS ON TIME OF HARVEST AND YIELD
When considering the effects of variation in stage of growth and development among vegetable crop plants on the yield of produce acceptable for processing, we must consider the portion or structures of the plant which are processed, especially when the structures processed consist partly of vegetative tissue and partly of reproductive tissue which must be harvested at a definite stage of growth and development (1).
A crop may be considered as a continuous leaf canopy with emphasis on total growth per unit area (3), as a leaf canopy with emphasis on total growth of a portion of the plants per unit area (2, 4 and 6) or as individual plants with emphasis on growth and uniformity of each plant (5).
When only the center head of broccoli is harvested, all plants must have the center head at a uniform size and stage of growth and development at a definite time for a single pick harvest, individual plants must be considered. Acceptable quality is a function of uniformity in spacing and density of the plants per area, the size of the plants, the size of the heads, only one head per plant, and stage of growth and development of the heads. The leaf canopy should be considered in terms of individual plants and the leaves on each plant should be considered as a unit. Competition then occurs among plants, or units in the population. Sacki reported that domination of larger plants over neighboring smaller ones became progressively greater during the growing season (5).
The objective of this trial was to determine the effects of the time of emergence of broccoli seedlings and plant density on the date that the plants produced heads of processing size and quality.