Masters Theses

Date of Award

12-1988

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant, Soil and Environmental Sciences

Major Professor

David L. Coffey

Committee Members

Carl Sams, Luther Wilhelm

Abstract

Two experiments were conducted during 1987 and 1988 at the University of Tennessee Plant and Soil Science greenhouse. "Premium Crop" broccoli (Brassica oleracea L. Group Italica) plants were grown to develop a database from which an empirical mathematical model for vegetative growth could be developed. A model predicting the time from seeding to visible bud and another model showing the development of the inflorescence were also investigated. Plants were grown in shaded chambers within a greenhouse at 30, 50, 70, and 100% of full sunlight. Light treatments were arranged in a randomized complete block design with 3 replications. The Photosynthetic Photon Flux (PPF) density was recorded at 1-minute intervals in each experimental unit from the time of seedling emergence through inflorescence development using quantum sensors. Growth was defined as the increase in leaf area and leaf number over the duration of the study. Models that fit the data well were developed. A non linear model and two linear models described vegetative growth very well, however the non-linear model would be difficult to use and therefore is not recommended. The model predicting the time to visible bud may support evidence of critical minimum light and time requirements. The model describing the inflorescence development did not fit well as seen in a low R2. Though the models developed generally fit very well, they were based on a very small database. There was no supporting field and greenhouse data to validate the models. For these reasons, the models developed in this study should be used as guides rather than final predictive models.

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