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Ethylene is important during the berry development and in the last stages of rachis development or rachis senescence. Since grapes develop in a cluster that comprises both the fruit berry and the nonfruit rachis, we measured the release of ethylene from both tissues. Detached berries from Vitis vinifera 'Ruby Seedless' and 'Thompson Seedless' showed that ethylene release peaks at the beginning of berry development and at veraison. Ethylene production in the rachis was higher than that in the berry and had an obvious peak before harvest in 'Thompson Seedless'. In both cultivars, ethephon treatment induced ethylene production in the rachis but not in the berry. Expression of 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO) genes showed diverse temporal and spatial patterns in 'Thompson Seedless' and 'Ruby Seedless'. For most gene family members, the low ACS expression levels were observed in berry and rachis. Expression levels of most of the ACS and ACO genes did not correlate with ethylene released in the same organ. The transcriptional level of VvACS1 did correlate with ethylene evolution in rachis of 'Thompson Seedless' during berry development and storage, which suggested that VvACS1 may have important roles in rachis senescence. In berries of 'Thompson Seedless' and 'Ruby Seedless', the transcriptional levels of VvACO1, VvACS2, and VvACS6 coincided with ethylene production, indicating possible roles in berry development. Expression of VvACS2-VvACO9 and VvACO1-VvACO3 was not consistent with ethylene production during storage or in response to ethephon treatment, which suggests that the expression of ACS and ACO was affected by other stress factors after harvest. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the floricane leaf nutrient content, vegetative growth, and yield of two blackberry (Rubus spp.) cultivars (Tupy and Xavante), in response to rate of potassium (K) fertilization (0.0, 2.1, 4.2, 6.2, or 8.3 g/plant of K). The research was conducted in a region of low chill (342 chill hours) in southern Brazil (lat. 31°40' 46.98 S, long. 52°26' 4.36 W), and soil with pH 5.9, organic matter (OM) 1.1% and K 58.0 g⋅m-3. In 2009, only calcium (Ca) and magnesium (Mg) leaf concentration were affected by K application, and leaf K level was considered below normal for blackberry in Brazil. In 2010 and 2011, leaf K of blackberry in Brazil increased linearly in both cultivars with an increase in applied K. However, leaf K of blackberry in Brazil only reached its recommended levels for optimal growth in 2010 with the application of 2.1 and 8.3 g/plant of K for 'Tupy' and 'Xavante', respectively. In 2011, an antagonistic relationship was seen between leaf nitrogen (N)/K and K/Ca and K/Mg ratios with increasing K rates, where increasing K rates were accompanied by a linear decrease in the N/K ratio and a linear increase in the K/Ca and K/Mg ratios. Micronutrients evaluated showed no significant response to applied rates of K. A decrease in floricane leaf concentration of phosphorus (P), iron (Fe), manganese (Mn), and zinc (Zn) was also observed over years of the study. Potassium fertilization rates influenced the vegetative growth of blackberries. 'Tupy' showed increased cane density and pruning weights with increased rates of K application up to 8.3 g/plant, whereas cane density was optimized in 'Xavante' at 4.2 g/plant. The fruit yield of 'Tupy' and 'Xavante' increased linearly with K application per plant in all three years, indicating that K fertilization may be limiting the yield potential of these cultivars. These results suggest that the current K fertilizer recommendations may need to be increased for optimal production in Brazil. [ABSTRACT FROM AUTHOR]

Strawberry production in the U.S. Intermountain West is limited by harsh climatic conditions and competition from domestic producers and imports. Using season extension methods to combat climatic conditions may be effective but generally increases production costs. This study evaluates the economic returns to implementing high tunnels, low tunnels, and in-ground supplemental heating to strawberry production (Seascape and Chandler cultivars) in northern Utah. The high tunnel provided a net return of $1,943.57 or $15,548.56 per hectare assuming eight high tunnels per hectare. The addition of low tunnels within the high tunnel led to a positive increase in net returns for 'Seascape' but not for 'Chandler' production. Supplemental in-ground heating increased net returns by up to 50% for both cultivars, primarily as a result of higher pre- season yield and market pricing. Study results find that season extension technologies can successfully increase net returns to strawberry production through early and increased yields, when strawberries are sold primarily through local direct markets. [ABSTRACT FROM AUTHOR]

Canopy architecture, yield components, berry composition, pruning weight, Ravaz Index, and midwinter primary bud cold hardiness of own-rooted 'Vidal blanc' (Vitis vinifera x 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. [ABSTRACT FROM AUTHOR]