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  • Author or Editor: Tara Baugher x
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A 2-year study was designed to test the effect of four growth-suppressing treatments on the incidence of nectarine [Prunus persica (L.) Batsch] pox, nectarine fruit quality, and the growth and nutritional status of nectarine trees. Root pruning was the only treatment that significantly reduced the incidence of nectarine pox. The percentage of red surface was increased by root pruning, foliar-applied paclobutrazol, and girdling. Root pruning and paclobutrazol suppressed extension shoot growth. Root pruning decreased fruit N, P, K, Mg, Mu, Fe, B, and Zn levels and increased fruit Ca. Results of the study support earlier observations that nectarine pox is associated with excessive shoot growth, excessive levels of fruit N and K, and low levels of fruit Ca. Chemical name used: Beta-[(4-chlorophenyl) methyl] -alpha-(1,1-dimethylethyl)-l-H-1,2,4 -triazole-l-ethanol (paclobutrazol).

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Photosynthesis, light (PAR) and transpiration were measured with an ADC portable infrared gas analyzer on apples and grapes. Measurements were taken on north and south sides of the rows, in the morning and afternoon, on sun and shade leaves, and with the leaf chamber in a horizontal position and in a natural leaf orientation position. Measurements were made on three cloudless days in August 1990 and 1991. Subsequently, fruit adjacent to sampled leaves were harvested and soluble solids determined. Sampled leaves were then harvested and leaf areas and dry weights measured. Correlation coefficients of variables were then subjected to analysis of variance to determine which techniques gave the best correlations. Grapes and apples responded differently. For grapes, soluble solids were most closely correlated to light and photosynthesis measurements when measured on south side shade leaves, while with apples, blush side soluble solids were best correlated with measurements on south side sun leaves in the afternoon. Specific leaf weight was best correlated to photosynthesis and light with grapes when measured on north side sun leaves and with apples when measured on the south side in the morning.

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Advances in horticultural production technology are often hindered by slow grower adoption. Low adoption rates are largely the product of skepticism, which can lead to weaknesses in the commercialization process and affect future research and product development. To better understand industry concerns and design effective outreach methods, an information technology survey was designed as part of the U.S. Department of Agriculture Specialty Crop Research Initiative project titled Comprehensive Automation for Specialty Crops (CASC). This study outlines the survey results from 111 participants at tree fruit meetings in the Pacific northwestern and eastern United States in 2009. Many of the misgivings about new automated technologies, such as equipment cost and reliability of harvest assist, sensor systems, and fully automated harvest machinery, were consistent across the country. Subtle differences appeared between the eastern U.S. and Pacific northwestern U.S. responses, including justifiable equipment price points and irrigation and pest concerns; these are likely attributable to regional differences in climate, operation size and scale, and marketing strategies. These survey data will help the project team better address grower concerns and uncertainty on a regional and national level, thereby improving adoption speed and rates after CASC-developed technologies are rolled out.

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Three growth suppression treatments were compared during 1991 to 1993 on `Stayman' apple (Malus domestica Borkh.) trees grown in the T-trellis and the MIA trellis systems. All treatments—root pruning, K-31 fescue (Festuca arundinacea Schreb.), and K-31 fescue plus root pruning—suppressed tree growth compared to the nontreated control, but results were inconsistent between years and systems. Sod or sod plus root pruning reduced terminal shoot length in both systems in 2 out of 3 years. Root pruning decreased shoot length in the T-trellis in 1992. Sod decreased trunk cross-sectional area in the T-trellis in 1993. Treatments did not affect 3-year average yield efficiency but did appear to increase biennial bearing. Sod, with or without root pruning, decreased fruit cracking in the T-trellis 69% and 42%, respectively, in 1992, and sod plus root pruning decreased cracking in the MIA trellis 50%. Sod reduced fruit diameter in the T-trellis in 1992. Secondary effects of growth suppression treatments included increased light penetration and improved fruit color. Sod decreased leaf N and Mg and increased leaf P, K, and Cu. The Oct. 1993 stem water potential gradient from root to canopy was more negative in the sod plus root pruning treatment, and the osmotic potential of rootsucker leaves in the combination treatment was greater than in the control, indicating that sod plus root pruning alters the distribution of water within a fruit tree.

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Increasing labor costs and changes in labor forces have prompted an increased demand for automation in specialty crop production. Implementation of technological innovations in the agricultural sector tends to be slow, thus this study investigated motivations and perceptions of technology. Using qualitative interviewing and analysis, this study used a diffusion of innovations framework to gain insight into what channels of communications impacted planned adoption rates and what aspects of technology influence the decision-making process. Interview participants emphasized the inevitability of implementing new technologies while considering the capital investment of more complex technology, changes in labor management to integrate technology, applicability of technology to current practices, and trust in technology designers.

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A bicultural team of Penn State Extension professionals assessed educational method and learning style preferences of Hispanic/Latino stakeholders who aspire to be next generation specialty crop growers and specialized horticultural managers. During 2014–16, team members conducted and evaluated bilingual programs in various formats, including in-depth workshops, model demonstration plots, on-farm trainings and tours, fact sheets and field guides, and videos. Postprogram surveys indicated formats that provided opportunities for active learning of research-based information applicable to participant operations were most successful. Purposive surveys and interviews identified further ways to adapt extension outreach and education for next generation growers. The top-rated methods of learning for Hispanic/Latino growers were on-farm demonstrations and study circles, tours of other growers’ farms, self-paced on-line courses and videos, and interactive workshops. Factors Hispanic/Latino grower survey respondents felt limited them from participating in educational activities or using extension resources were timing of program, cost, and location. Survey participants suggested extension might improve education and engagement with Hispanic/Latino growers by increasing the use of social media in Spanish, holding educational programs specifically for Latino farmers to increase networking opportunities, and holding educational events at the farms of Latino growers.

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Fruit of 10 `Delicious' apple (Malus domestica Borkh.) strains were harvested 149 days after full bloom in 1988. Fruit color was measured at four locations on each fruit at the midpoint between the stem and calyx end with a Minolta CR-200b portable tristimulus calorimeter. Anthocyanin content of corresponding skin disks was determined spectrophotometrically. Significant differences existed among strains in both the amount and distribution of anthocyanin around the fruit. High-coloring strains had a significantly higher anthocyanin concentration at both the blushed and the nonblushed surface when compared to low-coloring strains. A linear regression of anthocyanin content on the ratio of (a*/b*)2 provided an R2 = 0.59; precision was enhanced by using a separate equation for each strain (R2 = 0.80). Regressing log (anthocyanin) on L* using two linear splines yielded an R2 = 0.78. These relationships allow the use of a portable calorimeter for rapid, nondestructive estimation of fruit anthocyanin content in situ.

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During a 3-year study of bitter pit in commercial ‘Honeycrisp’ apple (Malus ×domestica) orchards, incidence was associated with low calcium (Ca) levels in fruit peel; high ratios of nitrogen (N), potassium (K), and/or magnesium (Mg) to Ca in fruit peel; excessive terminal shoot length; and low crop load. Peel N and Mg concentrations were negatively correlated and peel Ca concentration positively correlated with crop density (CD). Shoot length (SL) was not consistently correlated with peel N, Mg, or phosphorus (P) and was negatively correlated with only Ca. A two-variable model that included SL and the ratio of N to Ca explained more than 65% of bitter pit incidence. The model has implications for best management of the cultivar in the field and during storage.

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In three experiments, diameters of apples representing 7% to 30% of the fruit on a tree were measured at ≈60 days after full bloom. Using previously published regression equations, the early-season fruit diameter values were used to estimate apple fruit weight at harvest (FWH). At harvest, all fruit on sample trees were weighed and the distributions of estimated FWH for fruit measured early in the season were compared with distributions of the actual FWH for whole trees. Actual FWH was normally distributed for only one of the three experiments. Although the estimated mean FWH averaged for the 10 trees was within 9% of the actual mean FWH for all three experiments, the distribution of estimated FWH differed significantly from the actual distribution for all three experiments. All fruit were then assigned to appropriate commercial fruit sizes or box counts (number of fruit/19.05 kg). Fruit size tended to peak on the same four box counts for the estimated and actual populations, but the estimated populations had too few fruits in the small- and large-size box counts. Using early-season estimates of FWH, commercial apple growers and packers can predict fairly accurately the percentage of the crop that will fall into the peak box counts, but a more accurate early-season estimate of the fruit size distribution will likely require measuring 50% of the fruit on a tree.

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