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Bruce W. Wood and Deane Stahmann

An ever increasing cost:price squeeze on the profitability of pecan (Carya illinoinensis) farming is driving a search for alternate husbandry approaches. `Wichita' and `Western' trees maintained at relatively high tree population density, by mechanized hedge pruning and topping, produced greater nut yield than an orchard treatment in which tree population density was reduced by tree thinning (144% for `Wichita' and 113% for `Western Schley'). Evaluation of three different hedge pruning strategies, over a 20-year period, identified a discrete canopy hedge pruning and topping strategy using a 2-year cycle, as being superior to that of a discrete canopy hedge pruning and topping strategy using an 8-year cycle, but not as good as a continuous canopy hedge pruning and topping strategy using a 1-year cycle. An evaluation of 21 commercial cultivars indicated that nut yields of essentially all cultivars can be relatively high if properly hedge pruned [annual in-shell nut yields of 2200 to 3626 lb/acre (2465.8 to 4064.1 kg·ha-1), depending on cultivar]. Comparative alternate bearing intensity and nut quality characteristics are reported for 21 cultivars. These evaluations indicate that pecan orchards can be highly productive, with substantially reduced alternate bearing, when managed via a hedge-row-like pruning strategy giving narrow canopies [3403 lb/acre (3814.2 kg·ha-1) for `Wichita' and 3472 lb/acre (3891.5 kg·ha-1) for `Western Schley']. North-south-oriented (N-S) hedgerows produced higher yields that did east-west (E-W) hedgerows (yield for N-S `Wichita' was 158% that of E-W trees and N-S `Western Schley' was 174% that of E-W trees).

These data indicate that mechanized hedge pruning and topping offers an attractive alternative to the conventional husbandry paradigm.

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Elizabeth A. Baldwin and Bruce Wood

Unsaturated fatty acid oxidation results in rancid off-flavors in pecan [Carya illinoinensis(Wangenh.) K. Koch] kernels, which shortens shelf life under ambient conditions. For this reason kernels are stored under costly refrigeration. Edible coatings [hydroxypropyl cellulose (HPC) and carboxymethyl cellulose (CMC), plus various additives] were used to restrict oxygen contact with kernel associated fats by acting as a barrier to gas exchange. Fresh pecans were acquired from orchards, air-dried, shelled, and treated with various coating formulations. The kernels were then drained, dried, and stored several months in open air or perforated zip-lock plastic bags at 20 to 25 °C and periodically evaluated by 18 to 20 sensory panelists using a 9-point hedonic scale for appearance, shine, off-flavor or overall flavor, and texture. Coated kernels generally scored lower for off-flavor, and higher for overall flavor. Preliminary coatings resulted in a less preferred appearance, but modifications to formulations of subsequent coatings resulted in either improved appearance or had no effect on appearance of kernels compared with uncoated control. Coatings with CMC imparted a shine to coated kernels, but did not generally affect texture. Hexanal accumulation, a good indicator of rancidity, of the homogenate of kernels stored at ambient temperatures for 5 and 9 months was lower in kernels coated with CMC than in the uncoated control, with CMC coatings including α-tocopherol being most effective. Thus, CMC-based coatings exhibit potential for extending the shelf life of pecan kernels.

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Marcela Miranda, Xiuxiu Sun, Christopher Ference, Anne Plotto, Jinhe Bai, David Wood, Odílio Benedito Garrido Assis, Marcos David Ferreira, and Elizabeth Baldwin

, 1994 ). Usually resin coatings have low oxygen permeability properties, and shellac and wood resin are generally less permeable than waxes such as polyethylene, candelilla ( Hagenmaier, 2002 ), and carnauba ( Assis et al., 2008 ; Lin and Zhao, 2007

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Terri Woods Starman and James E. Faust

The objective was to provide options for hanging basket production schedules by varying the number of plants per pot (one to four) and the number of manual pinches per basket (zero to two). Several species were evaluated in Spring 1995 and heat tolerance was assessed throughout the summer. Plugs (82 plugs per flat) were transplanted into 25-cm hanging baskets in a 22/18°C (venting/night temperature set points) glasshouse. Bacopa speciosa `Snowflake', Brachycome iberidifolia `Crystal Falls', Helichrysum bracteatum `Golden Beauty', Scaevola aemula `New Blue Wonder', and Streptocarpella hybrid `Concord Blue' produced quality baskets with three or more plugs per basket and no pinch. Pentas lanceolata `Starburst' and Lysimachia procumbens (Golden Globes) produced quality baskets with fewer than three plants per basket if plants received at least one pinch, however length of growing time was increased. Pentas lanceolata `Starburst', Scaevola aemula `New Blue Wonder', and Streptocarpella hybrid `Concord Blue' proved to be heat tolerant, blooming throughout the summer. Bacopa speciosa `Snowflake', Brachycome iberidifolia `Crystal Falls', and Lysimachia procumbens (Golden Globes) were not heat tolerant, i.e., ceased developing flowers in June and resumed flowering in September. Bidens ferulifolium did not produce an acceptable quality hanging basket under any experimental treatments.

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Bruce W. Wood, Rufus Chaney, and Mark Crawford

The existence of nickel (Ni) deficiency in certain horticultural crops merits development of fertilizer products suitable for specific niche uses and for correcting or preventing deficiency problems before marketability and yields are affected. The efficacy of satisfying plant nutritional needs for Ni using biomass of Ni hyperaccumulator species was assessed. Aqueous extraction of Alyssum murale (Waldst. & Kit.) biomass yielded a Ni-enriched extract that, upon spray application, corrects and prevents Ni deficiency in pecan [Carya illinoinensis (Wangenh.) K. Koch]. The Ni-Alyssum biomass extract was as effective at correcting or preventing Ni deficiency as was a commercial Ni-sulfate salt. Foliar treatment of pecan with either source at ≥10 mg·L–1 Ni, regardless of source, prevented deficiency symptoms whereas treatment at less than 10 mg·L–1 Ni was only partially effective. Autumn application of Ni to foliage at 100 mg·L–1 Ni during leaf senescence resulted in enough remobilized Ni to prevent expression of morphologically based Ni deficiency symptoms the following spring. The study demonstrates that micronutrient deficiencies are potentially correctable using extracts of metal-accumulating plants.

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E.A. Baldwin and Bruce W. Woods

Pecans (Carya illinoinensis) are full of unsaturated fatty acids, which are subject to oxidative cleavage. This results in the development of rancid off-flavors, which render the nuts unmarketable. For this reason, pecans must be stored under costly refrigerated conditions. Furthermore, pecans usually undergo retail distribution and marketing at ambient conditions, which promote development of off-flavors. Application of cellulose-based edible coatings reduced off-flavor, and improved overall flavor scores while adding shine to the nuts during 14 months of storage under ambient conditions. Development of rancidity involves hydrolysis of glycerides into free fatty acids, oxidation of double bonds of unsaturated fatty acids to form peroxides and then autooxidation of the free fatty acids once the peroxides reach a sufficient level to perpetuate this reaction. One of the products of autooxidation is hexanal which is, thus, a good indicator of rancidity. Analysis of pecans by gas chromatography revealed that hexanal levels were reduced in coated nuts by 5- to over 200-fold compared to uncoated controls, depending on the coating treatment. Some of the coating treatments affected nut color, but overall flavor and appearance were improved by certain formulations.

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James M. Dangler and C. Wesley Wood

Collards (Brassica oleracea L. Acephala Group) were grown in spring and fall to evaluate the effects of N fertilizer rate (0, 56, 112, 168, and 224 kg·ha -1), cultivar (Blue Max and Vates), and within-row spacing (15, 23, and 30 cm) on yield and leaf mineral nutrient concentrations. Season, cultivar, and N rate interacted in their effects on yield. In spring, `Blue Max' yield increased linearly with N rate to 10.4 t·ha-1, whereas the highest `Vates' yield (7.0 t·ha-1) was obtained with 112 kg N/ha, and yield remained similar with additional N. In fall, `Blue Max' and `Vates' yields were highest (14.5 and 9.9 t·ha -1, respectively) with 112 kg N/ha. Leaf N and P concentrations increased quadratically and linearly, respectively, in response to N rate. Maximum yields were obtained with the 15-cm within-row spacing. Leaf N concentration increased linearly with increased plant population. The adequacy of the present sufficiency range for leaf Ca concentrations of field-grown collards is discussed.

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Fouad M. Basiouny and Floyde M. Woods

Applications of paclobutrazol (PP333), Daminozide (DZ), and Nutri-cal to rabbiteye blueberry (Vaccinium ashi Reade) was studied. The application of these chemicals at different concentrations was made in the fall and throughout the growing season. PP333, DZ and Nutri-cal induced variable effects on yield, inte rnal and external fruit qualities. Shelf-life of hand-harvested fruits responded favorably to each of these chemicals.

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Terri Woods Starman and P.T. Gibson

The effectiveness of uniconazole for height control of Hypoestes (Hypoestes phyllostachya Bak. `Pink Splash') was determined, and the persistence of uniconazole with chlormequat and daminozide for limiting stem elongation in a low-light interior environment was compared. Spray and drench applications of uniconazole decreased plant height linearly with increased concentration. Two uniconazole sprays at 5.0 mg·liter -1, 0.05 mg a.i./pot uniconazole drench, or two chlormequat sprays at 2500 mg·liter-1 resulted in equally aesthetic plant size for 0.4-liter pots. Chlormequat was more effective than uniconazole for reducing rate of growth in the postharvest environment. No difference in postproduction rate of growth occurred between two sprays at 5.0 mg·liter-1 and 0.05 or 0.10 mg a.i./pot drench treatments of uniconazole. Chemical names used: 2-chloro -N,N,N- trimethylethanaminium chloride (chlormequat chloride); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); (E)-(S) -1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-l1ene-3-ol (uniconazole).