One of the major objective of growth analysis data is to provide a basic understanding of some of the mechanisms that affect plant growth. This study was initiated to evaluate the effects on several growth parameters when plants are grown in an NFT system. Vine cuttings (15 cm length) of the sweetpotato cultivar ``Georgia Jet” was grown in a closed NFT system for a period of 120 days. Nutrient was supplied in a modified half-strength Hoagland's solution with a N:K ratio of 1:2.4. Destructive harvesting of plants occurred at 14 day intervals at which time plants were separated into their various component parts and analyzed for dry weight accumulation, leaf area index, crop growth rate, relative growth rate and net assimilation rate. Results showed dry weight distribution within the plant had a linear response for all component part evaluated. Greatest contributors to total plant dry weight was stem followed by leaves, fibrous roots, buds and flowers. However, once storage root production occurred it contributed the largest percentage to total plant dry weight. LAI was optimum at 80 days after planting (DAP) while CGR and RGR fluctuated throughout the growing season. Initially NAR was higher in foliage than storage roots but declined once storage root enlargement began, suggesting a translocation of assimilates to storage root.
An experiment was conducted in a greenhouse environment to determine the relationship between type of cutting and planting depth on sweetpotato [Ipomea batatas (L) Lam] storage root yield using the nutrient film technique. Vine cuttings of the cultivar 'TI-155' were planted in growth channels (122×15×15 cm) in modified half Hoagland's solution. Treatments consisted of cuttings with all leaves and shoot apex removed with two nodes inserted (2NB), cuttings with all leaves and shoot apex removed with five nodes inserted (5NB). and cuttings with four leaves and the shoot apex remaining with two nodes inserted (2NB-L). Plants were harvested 130 days after planting and yield data was taken. Plants in 2NB-L had a significantly lower percent dry matter than those of 2NB. Neither cutting type nor planting depth affected yield or yield related parameters.