Canopy architecture, yield components, berry composition, pruning weight, Ravaz Index, and midwinter primary bud cold hardiness of own-rooted ‘Vidal blanc’ (Vitis vinifera × Vitis rupestris) were measured in response to balanced pruning formula treatments of 20, 30, or 40 nodes retained for the first 454 g of dormant pruning weight and an additional 10 nodes for each additional 454 g and three cluster thinning levels of one, two, and two+ clusters per shoot in 2006 and 2007. Although the pruning formula affected the distance between shoots along the canopy, and the number of count shoots per hectare, the canopy leaf layer numbers were unaffected in either year. Application of the pruning formula did not affect components of yield in either year. However, the number of clusters and yield per vine were affected by cluster thinning treatments where they increased linearly with the decrease in its severity, explaining 73% and 77% of total variance in yield in 2006 and 2007, respectively. Pruning formula or cluster thinning did not affect berry composition substantially. Cluster thinning improved the percentage of mature nodes on shoots before a killing frost in both years. Cluster thinning to one or two clusters per shoot also improved the lethal temperature killing 50% of the primary buds compared with no cluster thinning in both years of the study. Mature wood weight and total pruning weight displayed a quadratic response to cluster thinning where two clusters per shoot had the greatest weight for both, whereas pruning formula had no effect on pruning weight. Optimum fruit weight–pruning weight ratio was achieved with the 30 + 10 pruning formula and two clusters per shoot cluster thinning treatments in both years of the study. The results of this study provide valuable information for growers of interspecific hybrids such as ‘Vidal blanc’ in the lower midwestern United States as well as in other regions with long, warm growing seasons. Balanced pruning to 30 nodes per 454 g of dormant prunings and cluster thinning to two clusters per shoots optimized yield, maintained fruit composition, improved primary bud cold hardiness, and achieved an optimum fruit weight-to-pruning weight ratio of 10.0 kg·kg–1. Thus, this approach should be used for ’Vidal blanc’ in the lower midwestern United States to sustain production.
Patsy E. Wilson, Douglas D. Archbold, Joseph G. Masabni, and S. Kaan Kurtural
Luis A. Ribera, Marco A. Palma, Mechel Paggi, Ronald Knutson, Joseph G. Masabni, and Juan Anciso
This study investigates the potential impact of food safety outbreaks on domestic shipments, imports, and prices of the produce industry. Moreover, the compliance costs associated with new food safety standards were also estimated. Three case studies were analyzed to assess these potential impacts: the muskmelon (Cucumis melo) outbreak of Mar.–Apr. 2008, the spinach (Spinacea oleracea) outbreak of Sept. 2006, and the tomato (Solanum lycopersicum) outbreak of June–July 2008. The results demonstrate that the costs incurred by producers because of food safety outbreaks in produce are far greater than preventing such incidents.
Kirk W. Pomper*, Joseph G. Masabni, Desmond R. Layne, Sheri B. Crabtree, R. Neal Peterson, and Dwight Wolfe
The pawpaw [Asimina triloba (L.) Dunal] has great potential as a new fruit crop. A pawpaw variety trial was established in Fall 1995 in Princeton, Ky. as a joint Kentucky State Univ.-Univ. of Kentucky research effort with the objective to identify superior varieties for Kentucky. A randomized block experimental design was used with 8 replicates of 28 grafted scion selections on seedling rootstock. Cultivars being tested included Middletown, Mitchell, NC-1, Overleese, PA-Golden, Rappahannock, Shenandoah, Sunflower, Susquehanna, Taylor, Tay-two, Wells, and Wilson. The other 15 clones were selections from the PawPaw Foundation. In 2002 and 2003, the following parameters were examined: tree survival, trunk cross-sectional area (TCSA), average fruit weight, total fruit harvested per tree, average fruit per cluster, total yield per tree, and yield efficiency. In 2003, 54% of the trees had survived, with `Susquehanna' (13%) showing the poorest survival. Based on TCSA, most selections displayed excellent vigor, with the exception of the selections: 5-5 and `Overleese'. Average fruit weight was greatest in 1-7-2 (194 g), 1-68 (167g), 4-2 (321 g), 5-5 (225 g), 7-90 (166g), 9-58 (176 g), 10-35 (167 g), NC-1 (180 g), `Sunflower' (204 g), and `Shenandoah' (168g), with the smallest fruit in `Middletown' (70 g), `Wells' (78 g), and `Wilson' (88 g). The selections `Wilson' (81), `Middletown' (75), and `Wells' (70) had the greatest average number of fruit per tree, whereas 4-2 (9), 5-5 (17) and 8-20 (15) the fewest. Yield efficiency and average fruit per cluster also varied greatly among selections. Several pawpaw selections in the trial show promise for production in Kentucky.