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  • Author or Editor: James A. Wolpert x
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Alternate bearing in pistachio (Pistacia vera L.) is correlated with crop load; a heavy crop on l-year-old wood appears to cause abscission of inflorescence buds on current wood. Defruiting heavily bearing trees before or during the period of nut growth stopped inflorescence bud loss. This relationship between crop and bud loss was affected by the fruiting status of neighboring shoots. Large defruited branches (> 5.5cm diameter). in fruiting trees had bud retention values (50% to 65%) equivalent to fully defruited control trees, but smaller branches showed reduced bud retention levels. Bud retention was increased 2- to 6-fold in small branches when neighboring branches were defruited. Nitrogen concentration of leaves in late August was positively correlated with the final bud retention percentage and inversely correlated with defruiting date.

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Abstract

Two photoperiod regimes, natural daylength (ND) and night interruption (NI) of ND with a white light source, were used to test the importance of photoperiod on growth parameters, cold acclimation, and root conductance of potted ‘Concord’ grapevines (Vitis labruscana Bailey). By 3 Sept., NI-treated plants had a greater percentage of shoots with actively growing apices and a greater number of nodes per shoot than those untreated. No differences were seen in effect of light treatment on the extent of shoot maturation, as evidenced by shoot color change from green to brown. No consistent differences in hardiness of primary buds or canes of the first 12 nodes could be attributed to light regime. Apical tissues were less hardy than basal tissues for all regimes early in the acclimation period (10 Sept.). Root conductance, measured as suction-induced water flow, decreased throughout the acclimation period but did not differ between light treatments. Results are discussed in light of current hypotheses and of evidence of interrelationships among photoperiod, shoot growth cessation, shoot maturation, and cold acclimation.

Open Access

Abstract

Variability of cluster weight, soluble solids, and titratable acidity of ‘Concord’ grapes (Vitis labruscana Bailey) was quantified with respect to several fixed and random factors. All 3 measurements were affected by cluster position while only cluster weight and soluble solids were affected by sunlight exposure. Estimates of variance components indicated that the greatest percentage variability was among vines. Variance components were used to examine efficient sampling plans that would detect a specified difference at a selected level of Type I error. Graphs illustrate various schemes of sample allocation which would achieve the desired level of precision.

Open Access

Industry involvement is a critical aspect of the Specialty Crops Research Initiative (SCRI). Both a mandate for need and funding are necessary from industry to develop a successful SCRI project. The National Grape and Wine Initiative (NGWI), a nationwide coalition representing all segments of the grape (Vitis sp.) industry including raisin, juice, fresh grape and wine interests, identified extension education as a critical need and charged its extension/outreach committee to concentrate on ensuring industry members are aware of and have access to findings from grape and grape products research. To achieve this goal, the committee decided that a comprehensive online information and educational resource would play an important role. In 2009, the eXtension Grape Community of Practice (GCoP) was funded by the SCRI. The NGWI was active in soliciting letters of endorsement and buy-in from the industry for the project. The Missouri Wine and Grape Board (MWGB) also contributed $20,000 per year for three years to help offset the matching requirement. Research-based grape proposals in subsequent rounds of the SCRI in 2010 and 2011 wishing to have the approval of NGWI have been strongly encouraged to include the GCoP as a portion of their extension component. For the 2011 round of SCRI proposals, this led to the GCoP being included in three projects, two of which were funded. Exploration of future avenues for funding will include subcontracts from other grant awards, NGWI, industry sponsorships, and other creative methods.

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