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Sorkel Kadir* and Edward Carey

High tunnel strawberry (Fragaria × ananassa) production experiment was conducted in south central Kansas, which consisted of two cultivars and four tunnels. The same experimental design was conducted under field conditions. The objectives of this study were to compare strawberry production and quality under high tunnels to those grown in the field and to assess the potential for high tunnels for early-season strawberry production. Plug plants of `Sweet Charlie' and `Chandler' were planted October 18. Plants were spaced at 12” × 12 “in double rows on raised beds covered with black plastic mulch. Protected plants under high tunnels had 100% winter survival rate compared to 60% of the field plants. Yield and berry quality of the high tunnel plants were by far better than those of field grown plants. Plant growth under high tunnels was about three to four fold higher than the unprotected field plants. `Sweet Charlie' flowered in early February and produced berries one week earlier than `Chandler'. Both cultivars were harvest from early April through late May at weekly interval. `Sweet Charlie' in early April produced an average berry weight of 14 g, soluble solids of 8 °Brix, and the largest average berry weight was 15 g. `Chandler' harvested late April produced larger berries than `Sweet Charlie' with the largest average berry weight of 35 g compared to 31 g for `Sweet Charlie'. In mid May, `Chandler' produced 72% higher yield than `Sweet Charlie'. High tunnel not only produced higher yield and better quality berries than field strawberries but it has a potential to produce early crop and extend the season production of strawberry in Kansas.

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Kristine M. Lang and Ajay Nair

between 2007 and 2012 (U.S. Department of Agriculture [USDA], National Agricultural Statistics Service, 2014 ). A high tunnel is a solar-heated, passively ventilated, plastic-covered structure that lengthens the growing season for high-value specialty

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B.W. Wood

Alternately bearing `Cheyenne' pecan [Carya illinoensis (Wangenh.) K. Koch] trees were studied to assess the temporal aspects of previous season fruit development on several reproductive and vegetative traits of horticultural importance. Action spectra were generated and used to identify the relative sensitivities of these traits to the temporal aspects of fruiting. Based on date of maximum rate of change in sigmoidal models fitted to these action spectra, the relative sensitivity of certain important growth and developmental parameters to fruit removal time was number of distillate flowers per terminal shoot > number of distillate flowers per flower cluster on lateral shoots> length of terminal shoots > percentage of lateral shoots with fruit= catkins per terminal shoot at top of the tree> percentage of terminal shoots with fruit > catkins per standard terminal shoot> shoots produced per l-year-old branch> percentage of l-year-old shoot death. Maximum rates of change for these reproductive and vegetative parameters were typically during the dough stage of ovule development; however, substantial change also occurred for several parameters over a much wider developmental window. No evidence was found for a hormone-like translocatable factor from developing fruit that either promotes or inhibits flowering. Extending the time from nut ripening to leaf drop increased production of staminate and distillate flowers the following year and appeared to increase fruit set.

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Eric D. Miltner, Gwen K. Stahnke, William J. Johnston, and Charles T. Golob

Late fall N fertilization of cool-season turfgrass in northern climates is a common practice. Previous research has been focused in climates where freezing temperatures prevail. Research in more moderate northern climates where turf may not go through winter dormancy is scarce. Four fertilizer N sources and an untreated control were applied in four different months (November, December, January, or February) to perennial ryegrass (Lolium perenne L.) in Puyallup, Wash., and to kentucky bluegrass (Poa pratensis L.) In Pullman, Wash., to compare their effects in moderate (Puyallup) and freezing (Pullman) winter climates. In Pullman, only November applications of ammonium sulfate (AmS) or polymer coated sulfur coated urea (PCSCU) enhanced winter turfgrass quality. In Puyallup, November or December application of AmS, PCSCU, or polymer coated urea (PCU) resulted in enhanced winter quality. Polymer coated urea yielded a delayed initial response and a longer residual effect in the spring. Isobutylidenediurea (IBDU) did not improve winter turf quality in either Pullman or Puyallup. Although there was no quality response following January fertilizer application, there was suppression of red thread [Laetisaria fuciformis (McAlpine) Burds.] symptoms in Puyallup, indicating N uptake. Late fall fertilizer N in eastern Washington should be confined to November, using soluble or more quickly available slow-release nitrogen fertilizers. The application window can be extended to December in western Washington, and more slowly available coated ureas can be effectively used.

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Lurline Marsh, Corrie Cotton, Elizabeth Philip, Salina Parveen, and Fawzy Hashem

Excessive amounts of poultry waste on the Delmarva Peninsula of the United States, coupled with the availability of yard waste, may be potential inexpensive nutrient sources for growing vegetables. However, these composts may contain unsafe microorganisms. This study, therefore, was conducted to determine the presence and persistence of biological agents in soil treated with poultry compost and yard waste. Tatsoi [Brassica rapa (Narinosa Group)] and spinach (Spinacia oleracea L. `F415' and `Seven R') were planted under a high tunnel to extend their fall growing season. Samples of soil–compost mixture and original poultry compost were collected once a month for 4 months. Escherichia coli O157:H7 in the samples was determined by enrichment and immunomagnetic separation, and was not detected in any of the soil-mixtures. However, this bacterium was detected in the original poultry compost in very low numbers. Plant leaves were harvested periodically. Results showed that tatsoi plants significantly produced larger leaves and higher fresh weight in soils amended with organic compost with the tendency for yield to increase with the increase in harvest date. Generally, the organic amendments did not influence size and total fresh weight of spinach leaves, although earlier harvests tended to produce significantly larger leaves and higher fresh weight.

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James E. Ells, Ann E. McSay, E. Gordon Kruse, and Gregory Larson

Squash (Cucurbita pepo L. var. pepo) plants were grown on black polyethylene mulch or on bare ground, with trickle or furrow irrigation, and received only natural rainfall, or natural rainfall plus half or all of the estimated supplemental irrigation water required as determined by an irrigation scheduling program. The squash roots predominate in the upper 6 inches of soil throughout the season, with no less than 60% of the root mass located in this layer. The proliferation of roots increased as they extended horizontally from the vertical center line of the plant from 0 to 24 inches. Neither the irrigation treatments nor black polyethylene mulch had any influence on the pattern of root development. Water stress, however, reduced the size of the root system and the crop yield. Yields were not influenced by either furrow or trickle irrigation on the short rows that were used in this study. However, black polyethylene mulch and full irrigation offered the best chance of maximizing squash yields under the conditions of this study.

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Virginia I. Lohr

. Weather extremes consistent with predictions from climate change and global warming models are already occurring. For example, the U.S. Environmental Protection Agency (EPA) reports that the growing season in the 48 contiguous U.S. states has been above

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Marvin D. Butler and Robert E. Rush

Early maturity is of major importance to table grape producers in Arizona and the California desert. However, table grapes in this region often experience a delayed and erratic budbreak thought to be due to a lack of chilling. The influence of three rates of hydrogen cyanamide on budbreak timing and uniformity was evaluated at a commercial vineyard near Dateland, Ariz., during the 1984-85 season. Treatments were made to three table grape cultivars over three application dates. Additional research to evaluate possible interaction between time of pruning and application of hydrogen cyanamide was conducted during 1985-86. Of the three application rates evaluated, the 5% solution provided optimal results, inducing a greater total number of buds to break for perlette and flame seedless cultivars than nontreated plots. Early application resulted in a significantly earlier but extended budbreak; later applications were more dramatic and uniform. Budbreak was accelerated by 1 to 2 weeks for perlette, and up to 2 to 3 weeks for flame seedless and Thompson seedless cultivars. Hydrogen cyanamide applications also had a positive influence on earliness of blossom and percent soluble solutes at harvest. Pruning up to 11 days before or 14 days after application of hydrogen cyanamide generally did not have a significant effect on budbreak or maturity at harvest.

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Peter A.W. Swain and Rebecca L. Darnell

Two cultivars of southern highbush blueberry (Vaccinium corymbosum interspecific hybrid) were grown in containers under the traditional deciduous production system, or the dormancy-avoiding evergreen production system. In the dormancy-avoiding system, plants are maintained evergreen and do not enter dormancy in the winter. This alleviates the chilling requirement, thus extending the potential growing area of blueberries into subtropical regions. Plants in the evergreen production system were maintained in active growth through weekly or biweekly N fertilization (≈21–23 g N/ plant per year). Keeping foliage through the year lengthens the duration of the photosynthetic season of the plant and is hypothesized to improve the carbohydrate (CHO) status of the evergreen plants. This, in turn, may decrease source limitations to reproductive development and potentially increase fruit number and/or size. In both cultivars, the evergreen production system advanced the time of anthesis by 3 to 4 weeks compared to the deciduous production system. Plants in the evergreen system initiated 10% to 25% more flower buds than plants in the deciduous system, depending on cultivar. Average leaf area, leaf fresh weight, total above-ground fresh weight, bud density, and cane length were greater in the evergreen plants than deciduous. The evergreen production system increased plant fresh weight and flower bud number compared to the deciduous system, and may ultimately increase yield.

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C.O. Gwathmey and A. E. Hall

Removal of pods from legume crops may extend reproductive duration by delaying leaf senescence. In two years of field experiments, cowpea (Vigna unguiculata [L.] Walp. cv. CB5) pods were continuously harvested as they reached color–break or southernpea stage. The largely monocarpic reproductive pattern of non-picked CB5 was altered to a bimodal distribution by picking. During the first podding period, removal did not appreciably change reproductive duration nor the number of pods produced. It reduced dry weight in seed 22–34% and significantly delayed leaf senescence relative to the non–picked control. This increase in source:sink ratio was accompanied by increasing starch concentrations in stems and was followed by generation of a second set of pods which doubled the reproductive duration of picked plants. By contrast, starch reserves declined during the first podset in senescent control plants, which produced few pods thereafter. Picked plants produced 41–60% more pods/m2 over the entire season than non–picked CB5, but total dry weight in seed did not differ significantly since pod removal limited aced fill.