UBC Theses and Dissertations
The influence of row covers and plant population density on the growth and productivity of bell peppers (Capsicum annuum L.) Gaye, Mary Margaret
An interlocking group of studies was conducted to examine the effects of row covers and plant population density on the growth and productivity of field-grown bell peppers. The studies were carried out at the Agriculture Canada Research Station, Agassiz, British Columbia, in 1988. Analysis of variance was used to determine treatment effects on reproductive and vegetative components of yield. A nonlinear regression model was used to define the yield responses. Yield components were assessed, at different stages of plant growth, for their contribution to reproductive and total plant yield variation, using a two-dimensional partitioning technique. The influence of growth and treatments on fruit and whole plant allometry was studied using a best subset multiple regression procedure. Row covers enhanced reproductive and vegetative yield per plant and per land area. Increasing plant population densities resulted in decreasing yield per plant, but increasing yield per land area. Furthermore, the effect of row covers on yield was greater at low population densities than high. The number of nodes was the most important contributor to variation in reproductive and total plant yield. Fruit weight as a proportion of total plant yield was also a major contributor to reproductive yield. The analysis showed the importance of row covers in the initial stages of growth, and the increasing importance of plant population density as growth proceeded, on yield components and on reproductive and total plant yield. Allometric relationships defining fruit and plant morphology changed during growth, and were also affected by row covers and plant population density. The changes were reflected through the allometric exponent and the allometric coefficient. Significant increases in horticultural yield resulted from the application of row covers and from high plant population densities. The response was quantified in mathematical models. Yield component analysis and allometric analysis of reproductive and total plant yield, proved to be valuable techniques for extending our understanding of plant growth relations resulting from the applied treatments.
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