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J.A. Anchondo, M.M. Wall, V.P. Gutschick, and D.W. Smith

Pigment and micronutrient concentrations of New Mexico 6-4 and NuMex R Naky chile pepper (Capsicum annuum L.) cultivars as affected by low Fe levels were studied under soilless culture. A custom-designed, balanced nutrient solution (total concentration <2 mm) was continuously recirculated to the plants potted in acid-washed sand (pot volume 15.6 L). Each set of plants from each cultivar received iron concentrations at 1, 3, 10, and 30 μm Fe as Fe-EDDHA. The pigments of leaves, green fruit, and red fruit were extracted with acetone and measured with a spectrophotometer. Surface color of green and red fruit was measured with a chromameter. Total concentrations of Fe, Cu, Zn, Mn, P, and K of leaf blades and red fruit were measured by inductively coupled plasma emission spectroscopy (ICP). Ferrous iron in leaf blades, and NO3-N in petioles also were determined. Iron nutrition level affected total leaf chlorophyll and carotenoid content at early season, and the level of these pigments in green fruit at second harvest. No differences in extractable or surface color of red fruit were found among iron treatments in the nutrient solution, despite variations in red fruit iron content, total foliar iron, and foliar ferrous iron. Higher levels of iron in the nutrient solution increased both ferrous and total iron of the leaves, but depressed foliar Cu and P. High iron supply also increased fruit iron, and decreased fruit Cu content. High iron levels in the nutrient solution were associated with higher concentrations of leaf pigments at early season and higher pigment concentration in green fruit.

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A.K. Carter, R.S. Stevens, J.R. Hamm, and N.W. Hopper

Twenty-eight seedlots of Capsicum annuum from several commercial seed companies were tested for tolerance to low temperatures. Each cultivar was tested three times at 25, 20, and 15°C in laboratory incubators. It was observed that while high germination percentages (r85%) and fast germination rates were found in several seedlots, the relationship was not strongly linked to type of chile, age of seed, or treatment temperature. Of the 28 seedlots, 14 came from companies which are in the top 10% in volume and sales. The other 14 seedlots were from smaller companies. Seventy-one percent of the seedlots with germination at r85% came from the top ten companies. Ninety-two percent of the seedlots with s85% came from small companies. To further test this finding, we randomly choose six seedlots from a small company and 6 seedlots from a small company. There was a clear delineation in germabiltiy between the small company and the large company. Our results indicate a trend that could have a negative impact on some chile seed markets. Electrical conductivity (EC) is commonly used to detect membrane leakage in seeds. Chile seed from 12 seedlots (6 from the large company and 6 from the small company) were soaked 18 hours at 25 and 5°C. There was a negative correlation (r 2 = 0.76) between the 15°C germination at 40 days and the EC. It is important to determine why membrane leakage varies in seedlots from different companies and whether the leakage is due to phenotypic or cultural factors, or due to management practices within the company.

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Edith Isidoro, Donald J. Cotter, and G. Morris Southward

Color loss of Chile pods (Capsicum annuum L.) weathered on and off the plant was compared to that of refrigerated powder of comparable pods. Pods were harvested at 4-week intervals, dried at 65C, and ground and analyzed for color. Powder from these fruit was stored at 2C and analyzed at 4-week intervals. Pods that were weathered on or off the plant lost redness at a rate about one-half of that for refrigerated powder during 84 days of storage or weathering.

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Paul W. Bosland and Max M. Gonzalez

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Fred T. Davies Jr., Sharon A. Duray, Lop Phavaphutanon, and Randy Stahl

The influence of P nutrition on gas exchange, plant development, and nutrient uptake of Capsicum annuum chile ancho `San Luis' and bell pepper `Jupiter' plants was studied. Plants were fertilized weekly using 250 ml of a modified Long-Ashton solution, containing 0, 11, 22, 44, 66 or 88 μg P/ml. Phosphorus stress was evident with both pepper cultivars at 0 and 11 μg P/ml, with reduced plant growth and development: leaf number and area and fruit, leaf, stem, root, shoot, and total plant dry weight. The root: shoot ratio was greatest at 0 μg P/ml, reflecting greater dry matter partitioning to the root system. Greater P stress occurred at 0 μg·ml–1 in `San Luis' compared to `Jupiter' (88% vs. 58% reduction in total plant dry weight compared to optimum P response). `San Luis' was also more sensitive to P stress at 11 μg P/ml than `Jupiter', as indicated by the greater reduction in growth responses. With increasing P nutrition, leaf tissue P increased in both cultivars with maximum leaf tissue P at 88 μg P/ml. In `San Luis', there were no differences in tissue P between plants treated with 0 and 11 μg P/ml, whereas the `Jupiter' plants treated with 0 μg P/ml had the lowest tissue P. Low P plants generally had the highest tissue N and lowest S, Fe, Mn, Zn, B, Mo, and Al. With both cultivars, gas exchange was lowest at 0 μg P/ml, as indicated by low transpiration (E), stomatal conductance (gs), and net photosynthesis (A). Internal CO2 (Cj) and vapor pressure deficit were generally highest at 0 μg P/ml, indicating that Cj was accumulating with lower gs, E, and A in these P-stressed plants. Generally, no P treatments exceeded the gas exchange levels obtained by 44 μg P/ml (full strength LANS) plants.

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Fred T. Davies Jr., Sharon A. Duray, Lop Phavaphutanon, and Randy Stahl

In two separate experiments, the influence of phosphorus nutrition on gas exchange, plant development, and nutrient uptake of Capsicum annuum chile ancho `San Luis' and bell pepper `Jupiter' plants were studied. Plants were fertilized weekly using 250 ml of a modified Long–Ashton solution (LANS) containing 0, 11, 22, 44, 66, or 88 μg P/ml. Phosphorus stress was evident with both pepper cultivars at 0 and 11 μg P/ml, with reduced plant growth and development: leaf number and area, fruit, leaf, stem, root, shoot, and total plant dry weight. The root: shoot ratio was greatest at 0 μg P/ml, reflecting greater dry matter partitioning to the root system. Greater phosphorus stress occurred at 0 μg P/ml in `San Luis' compared to `Jupiter' (88% vs. 58% reduction in total plant dry weight compared to optimum P response). `San Luis' was also more sensitive to phosphorus stress at 11 μg P/ml than `Jupiter' as indicated by the greater reduction in growth responses. With increasing P nutrition, leaf tissue P increased in both cultivars with maximum leaf tissue P at 88 μg P/ml. In `San Luis', there were no differences in tissue P between 0 and 11 μg P/ml plants, whereas 0 μg P/ml `Jupiter' plants had the lowest tissue P. Low P plants generally had the highest tissue N and lowest S, Fe, Mn, Zn B, Mo, and Al. With both cultivars, gas exchange was lowest at 0 μg P/ml, as indicated by low transpiration (E), stomatal conductance (gs), and net photosynthesis (A). Internal CO2 (Ci) and vapor pressure deficit were generally highest at 0 μg P/ml, indicating that Ci was accumulating with lower gs, E, and A in these phosphorus-stressed plants. Generally, no P treatments exceeded the gas exchange levels obtained by 44 μg P/ml (full strength LANS) plants.

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F.T. Davies Jr., V. Olalde-Portueal, H. M. Escamilla, R.C. Ferrera, and M.J. Alvarado

In a 3 × 3 factorial experiment, Chile Ancho pepper (Capsicum annuum L. cv. San Luis) plants were inoculated or not with VA - mycorrhizal (VAM) Glomus fasciculatum and a Glomus sps isolate from Mexico (ZAC-19). Long Ashton Nutrient solution (LANS) were modified to supply P at II, 22 or 44 μg/ml to containerized plants, grown in a greenhouse for 72 days. The container medium was a modified 77% sand, 13% silt, 9% clay soil collected from an agricultural production site in Irapuato, Guanajuato, Mexico. Both P and VAM enhanced plant growth and development. Increasing P enhanced leaf area, fruit, shoot and root dry weight and shoot/root ratio; the leaf area ratio (LAR) decreased. Greater VAM growth enhancement occurred at Il and 22, than 44 μg/ml P. Growth enhancement was greater with Glomus fasciculatum than the mixed Glomus sps isolate (ZAC - 19).

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Monica Ozores-Hampton and Brain Mardones

Intensive peat mining in Chile and worldwide produces a significant increase in production costs and less market availability. Alternative systems to promote peat mining sustainability are an immediate necessity. A viable alternative for replacing peat in tomato transplant production is to use worm castings or vermicompost. Vermicomposting is a biological process that relies on the action of earthworms (Eisenia sp.) to stabilize waste organic materials. The objective of this study was to evaluate the use of Ecobol-S® worm castings as a replacement for peat in tomato transplant production. Three experiments were designed using a randomized complete-block design containing two factors (planting date and worm casting rate). Tomatoes were seeded in a growth chamber using five growth media made up of the different ratios of worm castings, peat, and rice hulls [0:70:30 (control) 18:52:30; 35:35:30; 52:18:30; and 70:0:30], respectively. It was determined that Ecobol-S® worm castings have an adequate C:N and particle size for tomato transplant production. However, limitations were observed due to its high EC and low C content. During early fall, with high temperature in the growth chamber, it is not recommended to use worm castings in transplant production due to nutrient leaching caused by frequent irrigation. In mid-fall, it is recommended to use a rate of 35% worm castings, while in early winter it is recommended to use a rate of 52% to obtain strong and healthy transplants. Therefore, worm castings can be used as a viable alternative in the tomato transplant industry in Chile and possibly worldwide.

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M. Paredes and A. Lavín

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Paul W. Bosland and Jaime Iglesias