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Mohanjeet S. Brar, Jameel M. Al-Khayri, Teddy E. Morelock, and Edwin J. Anderson

Cowpea (Vigna unguiculata L.) is an important grain legume, which in developing countries provides much of the protein in human diets. A plant regeneration system for cowpea was developed. Cotyledons were initiated on MS medium containing 15 to 35 mg·L-1 benzylaminopurine (BAP) for 5 to 15 days. For shoot regeneration, the explants were transferred to a medium containing 1 mg·L-1 BAP. Regeneration percentage (1% to 11%) and the number of shoots (4 to 12 shoots per explant) were significantly influenced by genotype. The duration of culturing and BAP concentration in the initiation stage significantly affected the regeneration capacity. Explants initiated on 15 mg·L-1 BAP for 5 days resulted in the highest regeneration percentage. Conversely, the highest number of shoots was obtained from explants initiated on 35 mg·L-1 BAP. This is the first report of plant regeneration of U.S. cowpea cultivars.

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S.C. Phatak, D.R. Sumner, R.B. Chalfant, J.D. Gay, L.D. Chandler, R.L Bugg, and K.E. Brunson

Cover crops relay-cropped with vegetables with conservation tillage were compared with fallow conventional production for 10 years. Conservation till-relay received no pesticide and only one-quarter the recommended fertilizers. Winter cover provided significantly better weed control than conventional. Weed problems in relay occurred only in the rows where vegetables were planted. Legume winter covers increased soilborne organisms but did not influence root disease severity or postemergence damping-off. Thrips, aphids, and whiteflies were most frequent. These pests remained below the economic threshold with winter cover crop-relay. However, infestation of these pests and Colorado potato beetles was severe in conventional plots. Winter cover crops provided habitat for more than 14 beneficial insects.

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Greg D. Hoyt

A no-till sweetcorn strip-till tomato rotation was established to determine whether a grass or legume winter cover crop would provide greater summer mulch and more soil inorganic nitrogen from residue decomposition. Sweetcorn yields improved as N rate increased in rye residue and bare soil, but only increased at the 50 kg N/ha rate in vetch residue. Strip-till tomato yields improved with all N rates for all covers. Total soil N and C were greater in both the vetch and rye residue treatments than the bare soil. Fertilizer N addition did not affect changes in total N or C percentages. Greater soil nitrate was measured beneath vetch residue at spring planting than in the rye residue or bare soil surface.

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Misty J. Moore, Mohanjeet S. Brar, Jameel M. Al-Khayri, Teddy E. Morelock, and Edwin J. Anderson

Cowpea (Vigna unguiculata L.) is an important grain legume that is grown extensively in Africa, South America, India, and in the United States. This study investigated the effects of silver nitrate (AgNO3) on regeneration of cowpea cotyledon explants. Silver nitrate at 50 μm significantly increased percent regeneration in comparison to the control. The effect of duration of exposure was also determined with the ethylene inhibitor AgNO3. By exposing explants to 59 μm AgNO3 during different stages of culture, significant increases were actualized in percent regeneration and shoot number. The greatest percent regeneration was obtained when 59 μm AgNO3 was augmented to both the initiation and regeneration media or to only the regeneration media. These results indicate that the low percentage of regeneration of this genotype may be related to ethylene biosynthesis or metabolism. This study resulted in an improved regeneration system for the commercial cowpea cultivar Early Scarlet, and will be useful in developing a cowpea transformation system.

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Roland E. Roberts, Kenneth Gray, and Joseph J. Bryant

Breedlove Dehydrated Foods (BDF), the largest charitable dehydration plant in the world, is capable of dehydrating 6,000 lb. raw product/hr. BDF dehydrates and distributes nutritious fruits, vegetables, and legumes to charitable organizations which feed hungry people. At least 35,617 people die from hunger in our world every day! Thousands of tons of nutritious but slightly imperfect horticultural products are wasted yearly in the United States. Donations totaling $7.8 million funded construction of BDF. Texas A&M and Texas Tech Universities provided expertise to plan and operate BDF. BDF dehydrated over 30 million lb. of fruits and vegetables in the initial two years of operation. BDF is a model of people focused on an unusually high goal and working together.

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Michael W. Smith

Several new management tools and management practices are being developed for pecan. Major insect pests of pecan are pecan nut casebearer, hickory shuckworm, and pecan weevil. Sex pheromone attractants are being developed for each of these pests that improve monitoring. Also, a pecan weevil trap (Tedder's trap) was introduced recently that is more sensitive to weevil emergence than the previous trap. New models that predict critical periods for pecan scab infection are being tested. Certain legume ground covers are being tested to increase beneficial arthropods in the orchard for aphid control, and to supply N. Mulches are being investigated as an alternative to herbicide management for young trees. A mechanical fruit thinning method has been developed that increases fruit quality and reduces alternate bearing as well as stress-related disorders.

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Frank Kappel, Bob Fisher-Fleming, and Eugene Hogue

The relationship between the objective assessment of analytical measures of sweet cherry (Prunus avium L.) fruit quality and the corresponding sensory panel rating was studied. The optimum size, based on average fruit weight, for sweet cherries was 11 to 12 g. A nine-row or 29- to 30-mm-diameter sweet cherry would be the equivalent industry standard. When two separate panels were conducted with overlapping samples, panelists had similar results for optimum fruit size. The optimum color is represented by the #6 color chip of the prototype of the Centre Technique Interprofessionnel des Fruits et Légumes (CTIFL) scale (#5 in new commercial CTIFL chart). A fruit firmness between 70 and 75 using a Shore Instrument durometer was considered optimum. Minimum soluble solids concentration (SSC) for sweet cherries was between 17% and 19% and optimum pH of the juice was 3.8. The optimum sweet–sour balance was between 1.5 and 2 (SSC/ml NaOH).

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J.R. Heckman

In-season soil nitrate testing is most useful when there is reason to believe, based on field history, that N availability may be adequate. These reasons may include soil organic matter content, applied manure, compost, legumes in the rotation, or residual N fertilizer. Soil nitrate testing is not helpful when crops are grown on sandy, low organic matter content soils that are known from experience to be N deficient. Soil nitrate testing is useful for annual crops such as vegetables or corn for which supplemental N fertilization is a concern. Soil nitrate tests must be performed at critical crop growth stages, and the results must be obtained rapidly to make important decisions about the need for N fertilization. Soil nitrate-N (NO3-N) concentrations in the range of 25 to 30 mg·kg-1 (ppm) indicate sufficiency for most crops, but N fertilizer practice should be adjusted based on local extension recommendations.

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Kyle E. Bair, Robert G. Stevens, and Joan R. Davenport

Concord grape (Vitis labrusca L.) accounts for a majority of juice grapes produced in Washington State. Because synthetic nutrients are not permissible in USDA organically-certified production systems, legume cover crops are used to supply nitrogen (N) to the crop. In order to supply a sufficient amount of N, the cover crop must successfully establish and produce large quantities of biomass. This study evaluates how the planting date influences emergence and biomass production of hairy vetch (Vicia villosa subsp. villosa L.) and yellow sweet clover [Melilotus officinalis (L.) Lam.] when used as legume green manures. The research was conducted on a commercial vineyard and a research vineyard from 2003–05. Treatments for the study consisted of yellow sweet clover and hairy vetch planted in both the spring and fall. Plots receiving soluble N sources were planted with wheat (Triticum aestivum L.) or rye (Secale cereale L.). Because of the large relative seed sizes of rye, wheat, and hairy vetch compared to yellow sweet clover, these treatments established faster with good stands in 2004. In 2005, clover plots had high emergence and biomass production because of water management modifications. Biomass data from the commercial vineyard in May 2005 indicates that fall-planted vetch produced more biomass than spring-planted vetch. Fall-planted hairy vetch and yellow sweet clover in the research vineyard showed higher biomass production than spring- and fall-planted hairy vetch and yellow sweet clover. When hairy vetch and yellow sweet clover are planted in the fall, they generally have better seedling emergence and biomass production due to the heightened aggressiveness exhibited by competing weed species during late spring and summer.

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N.M. Madden, J.P. Mitchell, W.T. Lanini, M.D. Cahn, E.V. Herrero, S. Park, S.R. Temple, and M. Van Horn

Field experiments were conducted in 2000 and 2001 in Meridian, Calif. to evaluate the effects of cover crop mixtures and reduced tillage on yield, soil nitrogen (N), weed growth, and soil moisture content in organic processing tomato (Lycopersicum esculentum) production. The trial was set up as a randomized complete-block design with eight treatments consisting of a 2 × 3 (cover crop × tillage) factorial design, a fallow control (F) and a single strip-till (ST) treatment. Cover crop mixtures were either legumes (L), common vetch (Vicia sativa), field pea (Pisum sativum) and bell bean (Vicia faba), or those legumes with grasses (GL), annual ryegrass/triticale (Lolium multiflorum/xTriticosecale) in 2000; cereal rye (Secale cereale)/triticale in 2001. Tillage treatments included an incorporation of the cover crop at planting (IP), a delayed incorporation (DI) (17 to 19 days after planting), and no-till (NT). Due to regrowth of the annual ryegrass in 2000, tomato fruit yields in 2000 were reduced by 50% to 97% within all GL treatments. However, regrowth of the cover crop was not a problem in 2001 and yields were not different among treatments. Total percent weed cover was 1.6 to 12.5 times higher in NT than IP treatments in 2000 and 2.4 to 7.4 times higher in 2001 as weed pressure was mainly affected by tillage practices and less by cover crop type. In 2000, available soil N was 1.7 to 9.4 times higher in L than GL treatments and was significantly influenced by tillage, but there were no treatment effects in 2001 due to a 60% reduction in weed pressure and minimal or no cover crop regrowth. Soil moisture content did not differ between treatments in either year. These results demonstrate the importance of appropriate selection and termination of cover crops for their successful adoption in organic conservation tillage systems.