129Proc. Fla. State Hort. Soc. 128: 2015.

Proc. Fla. State Hort. Soc. 128:129–132. 2015.

Vegetable Section

Evaluation of Jalapeño Peppers under Different Shade Cloths

Wellington Farias araujo1, 2, Kati W. Migliaccio*3, DaKshina r. seal2, Bruce schaFFer2, anD eDvan alves chagas4

1Soil and Agricultural Engineering Dept., UFRR, Boa Vista, Roraima, Brazil2University of Florida, IFAS, Tropical Research and Education Center,

18901 SW 280th Street, Homestead, FL 330313University of Florida, IFAS, Agricultural and Biological Engineering Dept.,

P.O. Box 110570, Gainesville, FL 32611-05 704EMBRAPA, Boa Vista, Roraima, Brazil

AdditionAl index words. Capsicum annum, cladding, colored films

Plants utilize the full spectrum of visible light with different colors of the spectrum having differing effects on plant growth and development. This study investigated growth and yield responses of hot pepper (Capsicum annuum ‘Jalapeño’) to different colored shade netting in field conditions in Homestead, Florida. Jalapeño peppers were placed in cubic shade structures (1 m3) covered on the top and sides with either aluminet (50% light exclusion), white (30% light exclusion), red (30%, light exclusion), pearl (30% light exclusion), or black (50% light exclusion) or with no cover (control). Plant height, stem diameter, leaf chlorophyll index and net photosynthesis were measured periodically for plants in each shade cloth treatment. Dry weight was also determined for plants in each treatment. Leaf chlorophyll index did not differ among treatments. Stem diameter and plant height increased over time for all treatments but increased less for plants in the control (no shade) treatment than in the shade treatments. Net photosynthesis and the number of fruit per plant were greater in the aluminet treatment than in other treatments. Plant dry weight was not influenced by shade treatment.

The jalapeño peppers (Capsicum annuum ‘Jalapeño’), origi-nating from Mexico, are popular due to their nutrient content, pungency, flavor, color and taste (Nalliah and Ranjan, 2010). Burden (2012) reported that in the United States, demand for jalapeño and other hot peppers increases every year as the popu-larity of ethnic cuisine increases. California and New Mexico produce most of the hot peppers grown in the United States, but many Florida farmers grow hot peppers as a niche crop (Ozores-Hampton and McAvoy, 2014).

As the world’s population continues to increase, resulting in less space for agriculture but greater food demand, the amount of food that can be produced in a given space needs to increase. One practice that might increase yield for a given area is the use of different shade cloths. Recently, colored shade cloths designed specifically for manipulating plant growth and development have become available. Stamps (2009) discussed the use of these shade cloths on microclimate, vegetative growth, and fruit yield and quality. Fukuda et al. (1993) suggested that dry matter partitioning in plants could be affected by the spectral quality of

light. Plant response to different colors has been documented for many crops (Bastias and Corelli-Grappadelli, 2012). However, the effects are varied and plant responses may differ, even among cultivars of the same species (Stamps, 2009).

The objective of this study was to investigate the effects of light quality on growth and yield of jalapeño pepper by growing them under different colored shade cloths in field conditions in Homestead, FL.

Materials and Methods

This experiment was conducted outdoors at the Tropical Research Education Center (TREC; latitude: 25°26'37"N and longitude: 80°27'36"W) in Homestead, FL, which has a subtropical marine climate. During the experimental period, the average temperature was 23.6 °C, average relative humidity was 80.8%, total rainfall was 335 mm, average evapotranspiration was 3.3 mm/day and average solar radiation was 198.7 W/m2 based on data collected from the Florida Automated Weather network (FAWN: http://fawn.ifas.ufl.edu/) at TREC from 22 Dec. 2104 to 22 June 2105. The weather station was approximately 300 m from the study plot.

Seeds of jalapeño peppers (Capsicum annuum ‘Jalapeño’) were germinated in a general purpose growing medium (Promix®; Premier Tech Horticulture Inc., Quakertown, PA) in flats in a greenhouse. Thirty-five days after emergence, the

The first author thanks the CAPES, Brazil foundation, for the scholarship (Process: 2546-14-0). The authors also thank Mr. Frank Giglia for the shade cloth, Ms. Tina Dispenza for project assistance, and Ms. Ana Vargas for equipment assistance.*Corresponding author. Email: klwhite@ufl.edu

130 Proc. Fla. State Hort. Soc. 128: 2015.

seedlings were transplanted into 1.6-L individual pots contain-ing Promix® and placed outdoors with a drip irrigation system (Fig. 1). The experimental design was a completely randomized block with six treatments and four replications per treatment. The treatments consisted of placing plants in cubic structures (1 m3) with different shade cloths: aluminet (50% light exclu-sion), white (30% light exclusion), red (30% light exclusion),

Fig. 2. Mean height (cm) of jalapeño pepper over time under different color shade cloths.

Fig. 1. Trays with the jalapeño pepper seedlings (top). Jalepeño pepper plant in a pot with a tensiometer (center). Cages in the field (bottom).

pearl (30% light exclusion), black (50% light exclusion), and no shade cloth (control) (Fig. 1). The aluminet, white, red, and pearl were made by Polysack Plastic Industries (Negev, Israel). There were six treatments with four replications of 16 potted plants per treatment. Pots were placed inside cages with each cage representing a treatment replicate.

Tensiometers were installed in one pot of each treatment to monitor soil water tension. Plants were irrigated daily to maintain soil tension at about 10 kPa in the control treatment. Immediately after transplanting, plants were fertilized with 1 g of Osmocote Plus® 15-9-12 (N-P-K, Scotts-Sierra Horticultural Products, Maryville, OH) and 70 mL of a fertilizer solution containing 22 mL of Miracle Grow® fertilizer (Miracle-Gro Lawn Products Inc., Marysville, OH) in 3.79 L water. The following week (Dec. 30, 2014), 3g KCl, 3 g urea, and 3 g Osmocote Plus® were manually applied to each pot. Thereafter, each plant was manually fertilized with 70 mL of a solution containing 3 g Peters Professional® 20-20-20 (N-P-K) fertilizer (Everris NA Inc., Dublin, OH) per liter of water and 22 mL of Miracle Grow® per 3.79 L water. Following that, each plant was manually fertilized fortnightly with 10 g W/suretex 12-6-8 (N-P-K, Diamond R. Fertilizer, Winter Garden, FL) and 70 mLof a solution containing 3 g of Peters® 20-20-20 per liter of water, 22 mLof Miracle Grow® per 3.79 L of water, and 1 g Sequestrene 138 Fe (Becker Underwood, Ames, IA) per 3.79 L of water.

During the early stages of plant development, plants ex-perienced infestations of green peach aphids [Myzus persicae (Sulzer)], melon thrips (Thrips palmi Karny), silverleaf whitefly (Bemisia argentifolii Bellows and Perring) and pepper weevil (Anthonomus eugenii Cano). Therefore, abamectin (Agri-Mek®-Syngenta, Greensboro, NC), spinetoram (Radiant® SC–Dow AgroScience, Indianapolis, IN), sulforaflor (Closure® –Dow AgroScience, Indianapolis, IN), thiamethoxam (Actara®–Syn-genta, Greensboro, NC), Kocide® 3000 (Dupont, Wilmington, DE), and induce® (Helena Chemical Co., Collierville, TN) were applied as foliar spays to control those pests.

Plant growth and vigor were assessed by measuring plant height (cm), stem diameter (cm), leaf chlorophyll index [SPAD units determined with a SPAD 502 meter (Konica Minolta Inc., Osaka, Japan) and net photosynthesis [measured with portable gas exchange system (CIRAS 2, PP Systems, Inc., Amesbury,

131Proc. Fla. State Hort. Soc. 128: 2015.

Table 1. Mean height (cm) of jalapeño pepper under different color shade cloths. Days After Transplant (DAT)Treatment 60 75 90 150 165 178Aluminet 25.50 az 27.81 a 40.18 a 50.50 ab 57.68 ab 62.50 abWhite 23.68 a 27.10 a 36.37 b 45.77 bc 52.47 bc 59.27 abRed 22.87 a 26.94 a 35.00 b 44.00 bc 49.23 c 56.09 bPearl 22.25 a 24.31 a 35.31 b 45.31 bc 51.37 bc 58.31 abBlack 23.00 a 26.06 a 40.62 a 52.56 a 61.12 a 63.94 aControl 16.18 b 19.39 b 30.25 c 36.81 d 39.64 d 41.12 cAverage 22.25 25.26 36.29 45.82 51.92 56.87zMeans within a column with different letters indicate significant differences according to Tukey’s range test (P ≤ 0.05), n = 16.

Table 2. Leaf chlorophyll index of jalapeño pepper under different color shade cloth.

Days After Transplanting (DAT)Treatment 75 90 150 165 178Aluminet 63.49 az 62.15 ab 65.85 a 61.52 a 61.49 abWhite 65.85 a 58.03 bc 60.74 a 59.33 a 53.65 cRed 68.03 a 62.47 ab 62.33 a 64.32 a 62.88 abPearl 68.47 a 63.15 a 64.77 a 63.99 a 62.04 abBlack 67.40 a 61.79 ab 66.00 a 62.74 a 65.17 aControl 63.22 a 56.47 c 59.50 a 56.68 a 56.24 bcVC (%) 8.40 7.54 11.58 12.38 12.57Average 66.07 60.68 63.20 61.43 60.24zDifferent letters indicate significant differences according to Tukey’s range test (P ≤ 0.05), n = 32.

Table 3. Dry weight (g) of jalapeño pepper under different color shade cloths.

Treatment Roots Stem Leaves Shoot Root/ShootAluminet 183.4az 93.81a 51.62 ab 145.4 a 1.462 aWhite 219.6a 111.70a 61.68 a 173.3 a 1.212 aRed 222.1a 104.1a 62.17 a 166.3 a 1.362 aPearl 215.3a 102.71a 61.57 a 164.3 a 1.325 aBlack 206.2a 98.41a 54.11 ab 152.5 a 1.200 aControl 176.8a 76.92a 47.18 b 124.1 a 1.537 aVC (%) 29.2 30.54 16.57 24.26 28.09Average 203.9 97.94 56.39 154.3 1.35zDifferent letters indicate significant differences according to Tukey’s range test (P ≤ 0.05), n = 8.

Fig. 3. Net photosynthesis (μmol·m-2·s-1 CO2) of jalapeño pepper under different color shade cloths measured at 97 (clear bars) and 107 (shaded bars) days after transplanting (DAT). Different letters indicate significant differences among treatments according to Tukey’s test (P ≤ 0.05).

MA). At the end of the study period, two plants per cage were harvested, dried in an oven (Memment, East Troy, WI) at 70 °C for 48 h to a constant weight and then leaf, stem, root, and whole plant dry weights were determined.

Data were analyzed by one-way analysis of variance (ANOVA) and means were separated by Tukey’s studentized range test (P ≤ 0.05).

Results and Discussion

For all treatments, stem diameter (data not shown) and plant height increased over time showing typical plant growth and development (Fig. 2). These results are in agreement with Nalliah and Sri Ranjan (2010) who evaluated hot pepper growing in a capillary irrigation system.

From 60 DAT (days after transplanting) to the end of the experiment, plant height was lower in the control treatment than in any of the shade cloth treatments (Table 1). From 90 DAT to the end of the experiment, plants in the aluminet and black shade cloth treatments were taller than plants in the control treatment (Table 1).

No significant differences were observed among treatments for leaf chlorophyll index at 75, 150, and 160 DAT (Table 2). At 90 DAT, plants in the pearl treatment had the highest leaf chlo-rophyll index and plants in the control treatment had the lowest (Table 2). At 178 DAT, plants in the black treatment had the highest leaf chlorophyll index and plants in the white treatment had the lowest (Table 2). Thus, chlorophyll index measurements were not sufficiently consistent enough to indicate any effect of the treatments.

No significant differences among treatments were found for stem or root dry weights or the root/leaf dry weight ratio (Table 3). However, leaf dry weight was significantly different among treatments with the control treatment having lower leaf dry weight than any of the shade treatments (Table 3).

Significant differences in net photosynthesis among treatments were observed 97 and 107 DAT. Although, the lowest average value for this variable was presented by control plants, it was not significantly different from the other treatments, except for the aluminet treatment which showed the highest values for both measurements (Fig. 3).

132 Proc. Fla. State Hort. Soc. 128: 2015.

The number of fruit produced was significantly greater for plants in the aluminet treatment than in the other treatments (Fig. 4).

The results of this study indicate that growing jalapeno pep-per plants under shade cloth can have a positive effect on plant growth and development. Also, growth and development of this crop is impacted by the color of the shade cloth used.

Fig. 4. Number of jalapeño pepper fruit for plants grown under different color shade cloths.

Literature Cited

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Burden, D. and D. Huntrods. 2012. Bell and Chili Peppers. AgMRC (Agricultural Marketing resource Center), Iowa State University.

Fánor Casierra-Posada, Y.A. Matallana-Díaz · E. Zapata-Casierra. 2014. Growth of bell pepper plants (Capsicum annuum) affected by coloured covers. Gesunde Pflanzen 66:149–155

Fukuda N, Ikeda H, Nara M. 1993. Effects of light quality on the growth of tomato and kidney bean cultured by hydroponics under controlled environment. J. Soc. Agri. Struct. Japan 3(3):127–134 <http://www.agmrc.org/commodities__products/vegetables/bell-and-chili-peppers>.

Nalliah, V. and Ranjan, S. 2010. Evaluation of a capillary-irrigation system for better yield and quality of hot pepper (Capsicum annuum). Applied Engineering in Agriculture. 26(5):807–816.

Ozores-Hampton, M. and G. McAvoy. 2014. Jalapeño and Other Hot Pepper Varieties for Florida. Series HS1241, Department of Horticul-tural Science, UF/IFAS Extension, University of Florida, Gainesville.

Stamps, R. 2009. Use of colored shade netting in horticulture. Hort-Science 44(2):239–241.