Tomato (L.ycopersicon esculentum Mill.) seedlings were nutritionally conditioned with solutions containing factorial combinations of N at 25, 75, and 225 mg·liter -1, P at 5, 15, and 45 mg·liter-1, and K at 25, 75, and 225 mg·liter -1 to determine the effect of nutritional regimes on tomato transplant growth and quality. As N increased from 25 to 225 mg·liter-1, fresh shoot weight, plant height, stem diameter, leaf number, leaf area, shoot and root dry weights, and total chlorophyll increased. Nitrogen accounted for the major source of variation. Phosphorus effects were significant only in 1988; Pat 45 mg·liter-1 increased fresh shoot weight, plant height, stem diameter, leaf number, and leaf area in comparison to 5 and 15 mg·liter -1. Potassium did not significantly influence any of the growth variables measured in the study. For quality transplant production, nutrient solutions should contain at least N at 225 mg·liter-1, P at 45 mg·liter-1, and K at 25 mg·liter-1.
Regina R. Melton and Robert J. Dufault
Alexis M. Barbarin, Frank J. Williams, Greg T. Bettmann, Donald P. Hauber, and Harish H. Ratnayaka
'Knowledge of constitutive levels of gas exchange and antioxidant properties under unstressed conditions is critical for elucidating their potential roles in stress tolerance, planning cultural practices, and evaluating nutritional quality of vegetable crops. This greenhouse study reports gas exchange, photosystem II efficiency, and pigment and antioxidant profiles of two spinach cultivars [SpinaciaoleraceaL., cvs. Bloomsdale Long Standing (Bloomsdale) and Hybrid Tyee (Tyee)] with contrasting morphology. `Bloomsdale', the cultivar with more compact stature and larger leaves, had 47% greater photosynthesis (P net) than `Tyee'. Stomatal conductance (g s) and transpiration (E) were 94% and 46% greater in `Bloomsdale' than `Tyee', respectively. However, photosystem II efficiency (F v'/F m') was only 8% greater in `Bloomsdale' than `Tyee'. Instantaneous water use efficiency was similar in both cultivars. `Bloomsdale' had nonsignificantly greater concentrations of chlorophylls a and b, lutein, β-carotene and violaxanthin than `Tyee'. Both cultivars had similar, marginal α-tocopherol concentrations (<0.1 ng·g-1 FW). However, `Tyee' had a greater chlorophyll a:b ratio which, combined with lower g s and E, suggests a possible advantage for `Tyee' over `Bloomsdale' under relatively dry and high light conditions. Further studies must be conducted to compare nutritional quality of the two cultivars, based on constitutive levels of pigments and antioxidants. Greater gas exchange activity in `Bloomsdale' than `Tyee' appears to be due more to CO2 acquisition/metabolism than photosystem II efficiency or concentrations of pigments and antioxidants.
Jinsheng Huang* and Sieglinde Snapp
Potassium (K) and boron (B) nutrition play an important role in control of tomato quality. To evaluate the interactive effects of K and B on yield and fruit quality in fresh market tomatoes, two-year field experiments were conducted in 2002 and 2003 in Southwest Michigan, using the industry standard cultivar `Mountain Spring' and recommended practices for irrigated, staked fresh market production. Six treatments evaluated three fertilizer regimes applied during fruit development (1N:1K, 1N:2K and 1N:3K) and two weekly B foliar sprays (none and 300 mg·L-1 B) at fruit set stage. Increasing K concentration in the fertilizer increased K content in both leaf and fruit tissue, but reduced calcium content in leaf tissue. 1N:3K fertilizer treatment increased tomato shoulder check incidence. The overall total percent shoulder check defect was 32.7%, 33.5% and 38.2% for 1N:1K, 1N:2K and 1N:3K fertilizers, respectively. Weekly B foliar spray increased both tomato marketable yield and fruit quality. Less shoulder check incidence was obtained with a foliar B spray. Boron foliar spray also increased K content in fruit tissue for 1N:1K and 1N:2K treatments. The 1N:2K plus B foliar spray is recommended for improving tomato yield and quality.
Floyd M. Woods, William A. Dozier, Robert C. Ebel, Raymond Thomas, Monte Nesbitt, Bryan S. Wilkins, and David G. Himelrick
Changes in fruit quality attributes and antioxidative properties from six cultivars of thornless blackberries (Rubus sp.) (`Apache', `Arapaho', `Chester', `Loch Ness', `Navaho', and `Triple Crown') during four different ripening stages (red, mottled, shiny-black, and dull-black) were determined under Alabama growing conditions. Berry fruit samples were evaluated for pH, titratable acidity, total soluble solids, TSS/TA ratio, soluble sugars, vitamin C (reduced, oxidized and total), and antioxidant capacity (measured as trolox equivalent antioxidant capacity, TEAC). Significant variation among cultivars were noted in fruit quality attributes and antioxidative properties, which were influenced by maturity at harvest. An increase in fruit pH concomitant with a decline in titratable acidity (TA) was observed during ripening for all cultivars. Total soluble solids (TSS) values increased from 5.7% to 11.6%, with associated TSS/TA ratio values ranging from 11.92 to 63.56 in ripening fruit. Highest reducing and total sugar content were contained in dull-black fruit. Vitamin C content either declined or remained unchanged with ripening, and the pattern was dependent on cultivar, maturity at harvest and form determined. In general, antioxidant activity declined between red and dull-black ripening stages. The results suggest that the TSS/TA ratio may provide the best maturity index in determining optimal eating quality and antioxidant capacity in terms of TEAC value the best indicator of optimal nutritional quality as influenced by maturity at harvest.
Laurie Robinson-Hipple, Faye Propsam, James B. Calkins, and Bert T. Swanson
Media fertility, plant nutrient availability, and subsequent plant nutrition are critical factors in the production of quality landscape plant materials. The method of mixing slow-release fertilizers into the media prior to planting is becoming more widespread. This study evaluates different controlled-release fertilizers, their rates of release, and three methods of irrigation regarding water-use efficiency and effects on plant growth performance. The combined effects of fertility and irrigation practices on nutrient loss to the environment are also being monitored. Although the ranking of fertility treatments, based on plant quality, varied among species, Woodace 21–4–10, Sierra 17–6–10, Sierra High N (24–4–6, Scotts 20–7–10, (270–26.67 lb/yd3), Woodace 20–5–10, Polyon 25–4–12, Nutricote 18–6–8 (270–30 lb/yd3), and Nutricote 18–6–8 (270–20 lb/yd3) produced high-quality plants for most of the species evaluated. The control and Nutri-Pak 18–6–12 treatments resulted in relatively poor-quality plants across the board. The effects of irrigation techniques on leachate analysis are being completed.
V. Fernández-Ruiz, M.C. Sánchez-Mata, M. Cámara, M.E. Torija, C. Chaya, L. Galiana-Balaguer, S. Roselló, and F. Nuez
The characterization of Lycopersicon germplasm for internal quality properties is essential to choose suitable donor parents for breeding programs. When donor parents belong to species of subgenus Eulycopersicon, which are phyletically closer to L. esculentum Mill., the recovery of agronomic traits is faster. When using these materials, a careful selection of donor parents which could improve several internal quality properties allows the acceleration of these breeding programs. In this work, we combine general determinations, such as soluble solid content, titratable acidity, pH, total sugars, pectic substances and total protein contents with precise high-performance liquid chromatography (HPLC), quantitations of individual compounds (vitamin C; citric, malic, fumaric and oxalic acids; glucose, fructose, and sucrose), in order to obtain a more complete characterization of flavor intensity and nutritional properties in Lycopersicon germplasm. The multidimensional analysis of all these variables allows classification of several accessions of L. esculentum Mill. and L. pimpinellifolium (Jusl.) Mill., according to their usefulness for internal quality breeding programs of fresh tomato. The classification obtained and the comparison of accessions quality characteristics with selected controls show that five of the L. pimpinellifolium (Jusl.) Mill. accessions tested can be of great usefulness for being used in breeding for internal quality characteristics. A flavor intensity ≈625% higher than commercial hybrids was obtained in the best accession tested. Some of these L. pimpinellifolium (Jusl.) Mill. accessions showed better flavor intensity properties than a high SSC L. cheesmanii Riley control, traditionally used in internal quality breeding. In addition, three of the L. esculentum Mill. accessions tested with medium-to-high flavor intensity value could be useful in advanced stages of breeding programs.
Nixwell Mudau, Puffy Soundy, and Elsa du Toit
Bush tea (Athrixia phylicoides) belongs to the Asteraceae family. It is a popular beverage, commonly used as an herbal tea and for medicinal purposes. In some parts of South Africa, people consume or drink it as an aphrodisiac. Bush tea was grown under varying nitrogen (N), phosphorus (P) and potassium (K) levels in the four seasons to determine the seasonal nutrient requirements for improved quality. Treatment consisted of 0, 100, 200, 300, 400, or 500 kg·ha–1 N, P, or K in a randomized complete-block design under 50% shade nets. Three N, P, and K parallel trials were conducted per season (autumn, winter, spring, and summer). Total polyphenols were extracted using Folin-Ciaocalteau reagents and analyzed in a spectrophotometer. Results for the N trial suggested that total polyphenols increased quadratically in response to N nutrition during summer, winter, and spring, but not in autumn. The optimum N level was 300 kg·ha–1. The highest total polyphenol was 51.1 mg·g–1 in winter. For the P trial, total polyphenols also increased quadratically in response to P nutrition regardless of season. Again winter had the highest total polyphenols (46.8 mg·g–1). The optimum P level was 300 kg·ha–1. In the K trial, regardless of season, total polyphenols plateaued at 200 kg·ha–1 and the highest polyphenols were in winter (43.3 mg·g–1). Therefore, for improved total polyphenol content, 300 kg·ha–1 N and P and 200 kg·ha–1 K are recommended regardless of season.
J.P. Syvertsen, M.L. Smith, and B.J. Boman
Effects of salinized irrigation water on tree canopy and root growth, water use, foliar nutrition, and leaching losses below the rootzone were studied during a 2-year period using single tree lysimeters. Eighteen 6-year-old `Valencia' orange trees on either Carrizo citrange (CC) rootstock or sour orange (SO) rootstock were each transplanted into 7.8 m3 drainage lysimeters and irrigated with water having an electrical conductivity of 0.3, 1.6, or 2.5 dS m-1 from a 3:1 ratio of NaCl:CaCl2. Six additional trees (3 on each rootstock) were transplanted into soil without tanks. Trees outside the tanks were smaller, but nutritionally similar to the low salinity trees in lysimeters. Trees on CC were larger, had greater root densities, and were associated with less leaching of ions and nutrients into drainage water from the tanks than trees on SO. High salinity irrigation water reduced canopy growth and ET, but increased fibrous root dry weight. Trees on CC accumulated more Cl in leaves and in fruit juice than those on SO. Leaching loss of total N varied from 2-8% of that annually applied to trees, but up to 70% of the applied N and up to 80% of the applied K were leached from the blank tank with no tree. Salinized trees lost more N and K to drainage water, especially those on SO. Tree size, root density, and irrigation water quality can influence leaching losses beyond the rootzone.
Michael Gold, Mihaela M. Cernusca, and Larry Godsey
Edible chestnuts are an ancient tree crop undergoing a global renaissance. Scattered efforts are under way throughout the U.S. to develop domestic chestnut production based on chestnut cultivars from Europe or Asia. Concurrently, it is necessary to redevelop the domestic market by reintroducing the chestnut as a food crop to a new generation of U.S. consumers. A study was conducted to gauge the familiarity of participants with chinese chestnuts (Castanea mollissima), eastern black walnuts (Juglans nigra), and northern pecans (Carya illinoensis) to determine their interest in buying, consuming, and preparing these nuts and the key attributes that influence purchase decisions. The study also determined participants' interest in obtaining more information about the production, marketing, cooking, preparation, and nutritional information of nuts. Results of the study show that consumers were not familiar with chestnuts. Most had never tasted a chestnut, but did have interest in exploring them as a new food. Quality and nutrition-diethealth were consistently listed as the most important attributes influencing purchase and consumption decisions for chestnuts and black walnuts but for pecans, locally grown was the most important attribute.
K. Francis Salifu, Douglass F. Jacobs, Guillermo Pardillo, and Mary Schott
We examined growth and nitrogen (N), phosphorus (P), potassium (K), and microelement nutrition of grafted black walnut (Juglans nigra L.) seedlings exposed to increasing nutrient supply and grown in the greenhouse for 18 week. Plants were potted and grafted within the first 4 week, then fertigated once each week for a 7-week period with a varying nutrient solution of 20N–4.4P–16.6K that delivered 0, 1160, 2320, and 4620 mg N/plant. Plants were harvested at week 18. There was a positive mean growth response to increased fertilization, although trends were statistically similar across treatments. Leaf nutrient concentration ranged from 22 to 31 g · kg–1 N, 5 to 14 g · kg–1 P, and 19 to 25 g · kg–1 K. The 2320 mg N/plant treatment increased leaf nutrient content 18% to 86% for N, 33% to 303% for P, and 23% to 58% for K compared with the control. Nitrogen efficiency decreased with increased N supply. Increased nutrient retention in the growing medium at higher fertility suggests root plugs could serve as immediate critical nutrient sources for grafted black walnut seedlings after outplanting. Study results suggests nursery fertilization can be used to improve the nutritional quality of grafted black walnut as well as store nutrients in root plugs for later utilization to benefit early establishment success.