Influence of Daily Light Period and Irradiance on Yield and Leaf Elemental Concentration of Hydroponically Grown Sweetpotato

Growth chamber experiments were conducted to evaluate the effect of irradiance and daily light period on storage root yield and leaf elemental concentration of two sweetpotato cultivars grown hydroponically by use of the nutrient film technique (NFT). Stem cuttings (15 cm) of cv. Whatley/Loretan and Georgia Jet were grown in NFT channels (0.15 × 0.15 × 1.2 m) in reach-in growth chambers under light period/irradiance combinations of 18 h: 300 μmol·m−2·s−1 or 9 h: 600 μmol·m−2·s−1 photosynthetic photon flux. Temperature was 28/22 °C light/dark with a relative humidity of 70% ± 5%. Storage root and foliage yields were greater in both cultivars exposed to a longer daily light period and lower irradiance. The main effect of cultivar indicated that storage root yield was significantly greater among plants of ‘Whatley/Loretan’ compared with that of ‘Georgia Jet’, whereas foliage yield was similar between cultivars. Leaves of plants grown under longer daily light period and lower irradiance had significantly lower concentrations of all elements, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, iron, calcium, boron, and zinc, except for calcium, manganese, and boron. There were no significant differences in leaf elemental concentration between cultivars. Thus, a longer daily light and lower irradiance enhanced biomass production of sweetpotato but reduced leaf elemental concentration probably because of a “dilution” effect.

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Growth Responses of Hydroponically Grown Sweetpotato Tolerant and Intolerant of a Continuous Daily Light Period

HortScience ◽

10.21273/hortsci.31.2.209 ◽

1996 ◽

Vol 31 (2) ◽

pp. 209-212 ◽

Cited By ~ 6

Author(s):

D.G. Mortley ◽

P.A. Loretan ◽

W.A. Hill ◽

C.K. Bonsi ◽

C.E. Morris

Keyword(s):

Ipomoea Batatas ◽

Production Efficiency ◽

Elemental Concentration ◽

Light Period ◽

Photon Flux ◽

Storage Root ◽

Growth Responses ◽

Area Index ◽

Nutrient Film Technique ◽

Half Strength

Two sweetpotato [Ipomoea batatas (L.) Lam] genotypes (`Georgia Jet' and the breeding clone TI-155) were grown at 12-, 15-, 18-, and 21-h light/12-, 9-, 6-, 3-h dark cycles, respectively, to evaluate their growth and elemental concentration responses to duration and amount of daily lighting. Vine cuttings (15 cm long) of both genotypes were grown in rectangular nutrient film technique channels for 120 days. Conditions were as follows: photosynthetic photon flux (PPF) mean 427 μmol·m–2·s–1, 28C day/22C night air cycle, and 70% ± 5% relative humidity. The nutrient solution used was a modified half-strength Hoagland's solution. Storage root count per plant and per unit area, yield (in grams per square meters per day), and harvest index increased, while production efficiency (in grams per mole) decreased with increased daily PPF. Stomatal conductance for both genotypes declined with increased daily PPF. Leaves were smallest for both genotypes at the 21-h light period, while storage root yield declined as leaf area index increased. Except for a linear decrease in leaf N and K with increased light period, elemental concentration was not significantly influenced.

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232 Inverse Day/Night Temperature Influences Yield and Canopy Height of Hydroponically Grown Sweetpotato

HortScience ◽

10.21273/hortsci.35.3.431b ◽

2000 ◽

Vol 35 (3) ◽

pp. 431B-431 ◽

Cited By ~ 1

Author(s):

D.G. Mortley ◽

J.H. Hill ◽

C.K. Bonsi ◽

W.A. Hill ◽

C.E. Morris

Keyword(s):

Canopy Height ◽

Growth Chamber ◽

Photon Flux ◽

Root Production ◽

Storage Root ◽

Night Temperature ◽

Nutrient Film Technique ◽

Chamber Studies ◽

Growth Chamber Studies ◽

Hydroponically Grown

Growth chamber studies were conducted to determine if inverse day/night temperature could control canopy height of sweetpotato without adversely affecting storage root yield. Four 15-cm-long vine cuttings of TU-82-155 sweetpotato were grown in rectangular nutrient film technique hydroponic troughs for 120 days. Two troughs were placed into each of six reach-in growth chambers and subjected to 24/18, 26/20, 28/22, 18/24, 20/26, and 22/28 °C, respectively. Growth chamber conditions included a 12/12-h photoperiod, 70% RH, and photosynthetic photon flux of 1000 μmol·m-2·s-1 at canopy level. Total and edible storage root yields were reduced by 50% among plants grown under cool days/warm nights regimes. Harvest index was similar among treatments except for the low value obtained at 22/28 °C. Canopy height was positively correlated with the change in temperature, and for every 2 °C decrease there was a 3.1 centimeter decrease in canopy height. Inverse day/night temperature effectively controlled canopy height but at the expense of storage root production.

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Effect of fertilizer placement on storage root yield and leaf elemental concentration of Whatley/Loretan sweetpotato variety

African Journal of Agricultural Research ◽

10.5897/ajar2021.15549 ◽

2021 ◽

Vol 17 (10) ◽

pp. 1302-1307

Author(s):

S. Ahiabor Daniel ◽

G. Mortley Desmond ◽

K. Bonsi Conrad ◽

A. Bonsi Eunice

Keyword(s):

Elemental Concentration ◽

Storage Root ◽

Root Yield ◽

Fertilizer Placement

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Low-level Irradiance during the Dark Period Prevents Photoperiodic-induced Tuberization of Potato

HortScience ◽

10.21273/hortsci.33.3.542b ◽

1998 ◽

Vol 33 (3) ◽

pp. 542b-542 ◽

Cited By ~ 1

Author(s):

N.C. Yorio ◽

G.W. Stutte ◽

R.M. Wheeler ◽

L.M. Ruffe

Keyword(s):

Dark Period ◽

Light Period ◽

Photon Flux ◽

Dark Light ◽

Fluorescent Lamps ◽

Light Levels ◽

Nutrient Film Technique ◽

Early Maturing ◽

Metal Halide Lamps ◽

Inductive Photoperiod

The threshold irradiance during the dark portion of a photoperiod required to inhibit tuberization of potato (Solanum tuberosum L.) was investigated. Two cultivars of potato (cv. Norland, an early maturing variety; cv. Russett Burbank, a late-maturing variety) were grown using nutrient film technique hydroponics in separate tests within a walk-in growth chamber under a normally tuber-inductive photoperiod (12-h light/12-h dark). Light period photosynthetic photon flux (PPF) was provided by either daylight fluorescent lamps (providing 150 μmol·m–2·s–1 PPF) or a combination of daylight fluorescent and metal halide lamps (providing 300 μmol·m–2·s–1 PPF). The chamber was configured with vertically hung shadecloth and a pair of 15-W cool-white fluorescent lamps mounted at one end of the chamber to provide a range of low irradiance during the dark period. The low irradiance treatments averaged 3.65, 0.43, 0.06, and <0.01 μmol·m–2·s–1 PPF for the entire 12-h “dark” period. Results showed that tuberization occurred around 23 DAP, regardless of cultivar or light period PPF for plants grown with 0.06 and <0.01 μmol·m–2·s–1 PPF during the dark period. Tuberization also occurred at around 30 DAP for cv. Norland grown with 0.43 μmol·m–2·s–1 PPF during the dark period. No tubers were formed for either cultivar grown with 3.65 μmol·m–2·s–1 PPF during the dark period. These results indicate that light levels <0.43 μmol·m–2·s–1 PPF do not influence photoperiodic induction of tuberization in potato.

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EFFECT OF CONTINUOUS VS PERIODIC pH ADJUSTMENT ON GROWTH OF `GEORGIA JET' AND `T1-155' SWEET POTATO CULTIVARS GROWN USING THE NUTRIENT FILM TECHNIQUE (NFT)

HortScience ◽

10.21273/hortsci.25.8.864c ◽

1990 ◽

Vol 25 (8) ◽

pp. 864c-864 ◽

Cited By ~ 1

Author(s):

Edwin Martinez ◽

Conrad Bonsi ◽

Phili p Loretan ◽

Walter Hill ◽

Desmond Mortley ◽

...

Keyword(s):

Sweet Potato ◽

Nutrient Solution ◽

Life Support ◽

Growth Period ◽

Potato Cultivars ◽

Storage Root ◽

Root Yield ◽

Solution Ph ◽

Ph Adjustment ◽

Nutrient Film Technique

Sweet potato, selected as a potential food source for future long-term manned space missions, is being evaluated for NASA's Controlled Ecological Life Support Systems (CELSS) program. Greenhouse experiments were conducted to determine the effects of two pH treatments on the growth and storage root yield of `T1-155' and `Georgia Jet ' sweet potato cultivars. Vine cuttings of these cultivars were grown in a specially designed Tuskegee University NFT system. Plants were subjected to a continuous pH treatment in which the nutrient solution pH was maintained at 5.00 ± 0.10 throughout the growth period, and a periodic pH treatment in which the nutrient solution pH was adjusted to 6.00 at biweekly changeover intervals and when reservoirs were refilled with deionized water between biweekly changeovers. Results showed that for both cultivars the treatment with periodic pH adjustment had significantly higher storage root yield than treatment with continuous pH adjustment. This experiment is being repeated.

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IMPACT OF NUTRIENT REPLENISHMENT ON HYDROPONIC SWEETPOTATO CULTURE

HortScience ◽

10.21273/hortsci.31.5.761d ◽

1996 ◽

Vol 31 (5) ◽

pp. 761d-761

Author(s):

Audrey A. Trotman ◽

P. David ◽

D. Mortley ◽

J. Seminara

Keyword(s):

Electrical Conductivity ◽

Nutrient Supply ◽

Greenhouse Experiment ◽

Storage Root ◽

Root Yield ◽

Fresh Weight ◽

Hoagland Solution ◽

Set Point ◽

Nutrient Film Technique ◽

Nutrient Replenishment

In a greenhouse experiment, the effect of the addition of higher levels of potassium (K) in the replenishment stock used to supply nutrients in a nutrient film technique system was examined. For this study, `TU-82-155' sweetpotato was grown hydroponically for 120 days under four nutrient application/replenishment treatments: 1) REG—solution was changed at 14-day intervals and volume allowed to fluctuate; 2) MHH—replenishment with 10× concentrate of a modified half Hoagland solution (MHH) or with water to regain set volume (30.4 liters) and maintain set point of electrical conductivity (EC, 1050–1500 μmho); 3) MHH + 2K—daily replenishment with 10× concentrate of a modified half Hoagland solution (MHH) or with water to regain the set volume and adjust EC to 1400 followed by application of 50 ml of a 2K stock solution to an EC of 1500; 4) MHH/2K—replenishment with 10× concentrate of a modified half Hoagland solution that incorporated the 2K component or with water to regain set volume (30.4 liters) and maintain set point of electrical conductivity (EC, 105–1500 μmho). The storage root yield (g fresh weight per plant) was significantly higher when the 2K treatment was incorporated with the 10× MHH stock. The storage root yield averaged 324.8 g/plant compared with a yield of 289.6 and 252.9 g/plant, respectively, for the REG and MHH nutrient application protocol. As in earlier experiments, the MHH treatment was comparable to the REG protocol, validating the use of a replenishment approach for nutrient supply in hydroponic sweetpotato culture.

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Failure Analysis under Electric Lights: Growth and Yield of Sweetpotato in Response to 14 Days of Prolonged Darkness

HortScience ◽

10.21273/hortsci10637-16 ◽

2016 ◽

Vol 51 (12) ◽

pp. 1479-1481

Author(s):

Desmond G. Mortley ◽

Douglas R. Hileman ◽

Conrad K. Bonsi ◽

Walter A. Hill ◽

Carlton E. Morris

Keyword(s):

Ipomoea Batatas ◽

Dry Weight ◽

Growth And Yield ◽

Photon Flux ◽

Storage Root ◽

Growth Responses ◽

Root Yield ◽

Fibrous Root ◽

Storage Roots ◽

The Impact

Two sweetpotato [Ipomoea batatas (L.) Lam] genotypes (TU-82-155 and NCC-58) were grown hydroponically and subjected to a temporary loss of lighting in the form of 14 days of prolonged darkness compared with a lighted control under standard daily light periods to determine the impact on growth responses and storage root yield. Vine cuttings of both genotypes were grown in rectangular channels. At 65 days after planting, lights were turned off in the treatment chambers and replaced by a single incandescent lamp, providing between 7 and 10 µmol·m−2·s−1 photosynthetic photon flux (PPF) for 18 hours, and the temperature lowered from 28/22 °C light/dark, to a constant 20 °C. Plants remained under these conditions for 14 days after which the original light level was restored. Growth chamber conditions predark included, a PPF mean provided by 400-W metal halide lamps, of 600 ± 25 µmol·m−2·s−1, an 18-hour light/6-hour dark cycle and a relative humidity of 70% ± 5%. The nutrient solution used was a modified half-Hoagland with pH and electrical conductivity (EC) maintained between 5.5–6.0 and 1000–1200 μS·cm−1, respectively, and was adjusted weekly. Storage root number and fresh weight were similar regardless of treatments. Plants exposed to prolonged darkness produced 10.5% and 25% lower fibrous root fresh and dry mass, respectively, but similar foliage yield and harvest index (HI). ‘NCC-58’ produced an average of 31% greater storage root yield than that of ‘TU-82-155’ but the number of storage roots as well as % dry matter (%DM) were similar. ‘NCC-58’ also produced 31% greater fibrous root dry weight, whereas ‘TU-82-155’ produced a 44% greater HI. The significant interaction between prolonged darkness and cultivars for %DM of the storage roots showed that DM for ‘TU-82-155’ was 18.4% under prolonged darkness and 17.9% in the light. That for ‘NCC-58’ was 16.4% under prolonged darkness compared with 19.4% (14.8% greater) for plants that were not subjected to prolonged darkness. The evidence that there were no adverse impacts on storage root yield following the exposure to prolonged darkness suggests that the detrimental effects were below the detectable limits for these cultivars in response to the short perturbation in the available light and that sweetpotatoes would be hardy under short-term failure situations.

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Foliage Removal Influences Sweetpotato Biomass Yields in Hydroponic Culture

HortScience ◽

10.21273/hortsci.30.5.1000 ◽

1995 ◽

Vol 30 (5) ◽

pp. 1000-1002 ◽

Cited By ~ 4

Author(s):

P.P. David ◽

A.A. Trotman ◽

D.G. Mortley ◽

C.K. Bonsi ◽

P.A. Loretan ◽

...

Keyword(s):

Growth Rate ◽

Ipomoea Batatas ◽

Linear Growth ◽

Canopy Cover ◽

Linear Growth Rate ◽

Shoot Biomass ◽

Storage Root ◽

Root Yield ◽

Nutrient Film Technique ◽

Half Strength

Greenhouse studies were conducted to determine the effect of harvesting sweetpotato [Ipomoea batatas L. (Lam.)] foliage tips (terminal 15 cm) on storage root yield, edible biomass index (EBI), and linear growth rate. Plants were grown hydroponically from 15-cm vine cuttings planted in 0.15 × 0.15 × 1.2-m growth channels using a recirculating nutrient film technique system. Nutrients were supplied from a modified half-strength Hoagland solution with a 1 N: 2.4 K ratio. Foliage tips were removed at 14-day intervals beginning 42 days after transplanting. Final harvest was at 120 days after planting. At the end of the growing season, harvested foliage tips totaled 225 g/plant (fresh mass). Foliage removal significantly reduced storage root yield, shoot biomass, and linear growth rate expressed on a canopy cover basis. The EBI was higher for plants with foliage removed than for the control.

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SWEETPOTATO GROWTH AND YIELD IN NFT AS AFFECTED BY TYPE OF CUTTING AND PLANTING DEPTH

HortScience ◽

10.21273/hortsci.28.4.267f ◽

1993 ◽

Vol 28 (4) ◽

pp. 267F-267

Author(s):

Lauren Garner ◽

Desmond Mortley ◽

Philip Loretan ◽

Audrey Trotman ◽

Pauline David

Keyword(s):

Shoot Apex ◽

Dry Matter ◽

Growth And Yield ◽

Storage Root ◽

Root Yield ◽

Yield Data ◽

Planting Depth ◽

Ipomea Batatas ◽

Nutrient Film Technique ◽

The Relationship

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.

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