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Thomas H. Boyle, Lyle E. Craker, and James E. Simon

Plants of rosemary [Rosmarinus officinalis L. (Lamiaceae)] were grown in pots containing a soilless (1 sphagnum peat:1 perlite) or soil-based (1 sphagnum peat: 1 perlite:1 field soil) growing medium and fertilized with either 12N-5.2P-12.5K controlled-release fertilizer (CRF) at 9.0 g/pot; constant liquid fertilization (LF) with 20N4.3P-16.7K at 150 mg N/liter; constant LF at 150 mg N/liter, plus CRF at 4.5 g/pot; weekly LF at 150 mg N/liter; or weekly LF at 150 mg N/liter, plus CRF at 4.5 g/pot. Constant LF plus CRF generally reduced plant height and depressed shoot fresh weight relative to other fertilizer regimes. Essential oil content was highest in plants receiving weekly LF. Plants grown in the soil-based mix were shorter, shoot fresh and dry weight tended to be lower, and essential oil yield was higher when compared to plants grown in the soilless mix. Satisfactory growth was obtained in both media when rosemary plants were fertilized with 12N-5.2P-12.5K CRF at 9.0 g/pot or weekly LF with 20N<.3P-16.7K at 150 mg N/liter.

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Jay Frick, S. Suzanne Nielsen, and Cary A. Mitchell

Effects of N level (15 to 30 mm), time of N increase (14 to 28 days after planting), and planting density (1163 to 2093 plants/m2) were determined for crop yield responses of dwarf, rapid-cycling brassica (Brassica napus L., CrGC 5-2, Genome: ACaacc). Crops were grown in solid-matrix hydroponic systems and under controlled-environment conditions, including nonsupplemented (ambient) or elevated CO2 concentrations (998 ± 12 μmol·mol-1). The highest seed yield rate obtained (4.4 g·m-2·day-1) occurred with the lowest N level (15 mm) applied at the latest treatment time (day 28). In all trials, CO2 enrichment reduced seed yield rate and harvest index by delaying the onset of flowering and senescence and stimulating vegetative shoot growth. The highest shoot biomass accumulation rate (55.5 g·m-2·day-1) occurred with the highest N level (30 mm) applied at the earliest time (day 14). Seed oil content was not significantly affected by CO2 enrichment. Maximum seed oil content (30% to 34%, dry weight basis) was obtained using the lowest N level (15 mm) initiated at the latest treatment time (day 28). In general, an increase in seed oil content was accompanied by a decrease in seed protein. Seed carbohydrate, moisture, and ash contents did not vary significantly in response to experimental treatments. Effects of N level and time of N increase were consistently significant for most crop responses. Planting density was significant only under elevated CO2 conditions.

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D.G. Mortley, C.K. Bonsi, W.A. Hill, and C.E. Morris

`Georgia Red' peanut (Arachis hypogaea L.) was grown hydroponically at 20/16 °C, 24/20 °C, 28/24 °C, and 32/28 °C, day/night air temperatures to evaluate effects on pod and seed yield, flowering, harvest index, and oil content. Ten-day-old peanut seedlings were transplanted into rectangular nutrient film technique troughs (0.15 × 0.15 × 1.2 m) and grown for 110 days. Growth chamber conditions were as follows: photosynthetic photon flux (PPF) mean of 436 μmol·m-2·s-1, 12 h light/12 h dark cycle, and 70% ± 5% relative humidity. The nutrient solution used was a modified half-Hoagland with pH and electrical conductivity maintained between 6.5 to 6.7, and 1000 to 1300 μS·cm-1, respectively, and was replenished weekly. Vegetative growth (foliage, stem growth, total leaf area, and leaf number) was substantially greater at increasingly warmer temperatures. Reproductive growth was significantly influenced by temperature. Flowering was extremely sensitive to temperature as the process was delayed or severely restricted at 20/16 °C. The number of gynophores decreased with temperature and was virtually nonexistent at the lowest temperature. Pod yield increased with temperatures up to 28/24 °C but declined by 15% at the highest temperature (32/28 °C). Seed yield, maturity, and harvest index were highest at 28/24 °C. Oil content (percent crude fat) increased an average of 23% and was highest at the warmest temperature (32/28 °C). These results clearly suggest that vegetative and reproductive growth, as well as oil content of peanut in controlled environments, are best at warmer temperatures of 28/24 °C to 32/28 °C than at cooler temperatures of 20/16 °C to 24/20 °C.

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Nadia M. Abdalla, Ahmed A. Al-Badawy, Mohamed K. Ali, and Mervat A. Abd Al-Azeem

Mexican marigold (Tagetes minuta, L.) plants were fertilized with urea, nitrokima and ammonium nitrate at the rates of 0, 25, 50 and 100 kg N/feddan (feddan = 4200 sqm). These fertilizers were added at three batches during the growing season.

The application of nitrogen fertilizers enhanced plant growth in terms of plant height, stem diameter, branch number and the dry weights of leaves, flowers and herb. Also, these fertilizers increased the volatile oil content in the leaves and flowers. The most effective fertilizer was ammonium nitrate especially when the highest rate was applied as it gave 3.87 g/plant compared to 2.28 g/plant for the control plants.

The contents of photosynthetic pigments, reducing and total soluble sugars were increased compared to the control plants.

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L. Sistrunk, D. Chapman, and J. B. Storey

Pecan nuts from eleven different locations ranging from 1000 heat units at Chetopa, Kansas during the twelve weeks prior to shuck split to 1675 heat units in Zavala County, TX. Monounsaturated and polyunsaturated fatty acids increased and decreased respectively in `Mohawk' in 1991 and 1992 as the temperature increased during the kernel development period Fatty acids in `Pawnee' responded the same as in `Mohawk' in 1992 but were variable in 1991. Limited data showed a reversal of mono and polyunsaturated fatty acids in `Osage' in response to kernel development temperature. Higher temperatures caused the testas of `Cheyenne' to be darker in 1991 and 1992. Total oil content of `Mohawk' increased heat units. However, higher temperatures decreased oil content in `Pawnee'. Clinical evaluation of pecans is needed to confirm Grundy's safflower work.

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Peter J. Hofman, Marcelle Jobin-Décor, and Janet Giles

The potential to use percentage of dry matter (DM) and/or oil of the flesh of `Hass' avocado as a maturity standard to determine the latest harvest for acceptable fruit quality, was investigated. `Hass' avocado fruit were harvested from early October to mid-January from a commercial orchard in subtropical Queensland. The percentage of DM and oil changed little during the harvest period, and the eating quality of the flesh remained high. However, the incidence of body rots (caused mainly by Colletotrichum sp.) and the flesh disorders grey pulp and vascular browning, increased with harvest. These results indicate that percentage of DM and oil are not reliable late-maturity standards because of the inconsistent change with later harvests, and that disease and internal disorders can be the main determinants of latest acceptable harvest, rather than eating quality.

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Valtcho D. Zheljazkov, Tess Astatkie, Thomas Horgan, and S. Marie Rogers

; MIRC, 2009 ). If the distillation wastewater from an aromatic crop is shown to have growth-promoting effects on peppermint and spearmint or improve their essential oil content, such an extract could be applied to large-scale production systems, bringing

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Bahlebi K. Eiasu, Puffy Soundy, and J. Martin Steyn

. Similarly, Simon et al. (1992) reported that moderate water stress imposed on sweet basil resulted in higher oil content and greater total oil yield. Furthermore, the authors indicated that water stress changed essential oil composition: water stress

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Valtcho D. Zheljazkov, Tess Astatkie, and Ekaterina Jeliazkova

increase carvone concentration of ‘Scotch’ spearmint ( Zheljazkov and Astatkie, 2011a ). In another study, the application of MJ had no significant effect on essential oil content of ‘Native’ spearmint ( Zheljazkov et al., 2010b ). In the same study, the

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Valtcho D. Zheljazkov, Tess Astatkie, Thomas Horgan, Vicki Schlegel, and Xavier Simonnet

, 1973 ). Like with other aromatic plants, A. annua essential oil content and composition is modified by genotype and the environment ( Tzenkova et al., 2010 ), by distillation method ( Scheffer, 1993 ), and by other factors. A recent report ( Ferreira