UCCE efforts improve quality of and demand for fresh produce at WIC A-50 stores

In 2005, the Institute of Medicine recommended major revisions in the food packages provided by the federal Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), leading to new regulations that allow participants to purchase a wide variety of fruits and vegetables with their vouchers. In support of this policy change, UC Agriculture and Natural Resources Cooperative Extension (UCCE) developed educational materials to promote fresh produce among WIC participants and offered postharvest handling training at WIC-only stores, known as A-50 vendors, in order to improve produce quality. A survey conducted after the educational sessions found that WIC participants had increased knowledge of produce and A-50 vendors showed improved postharvest handling after the education sessions. This research demonstrates that combining nutrition education with postharvest handling curriculum can lead to a successful educational program that supports increased demand among WIC participants for fresh produce

UC Cooperative Extension explores a farm-to-WIC program

To increase fruit and vegetable consumption, the federal Special Supplemental Nutrition Program for Women, Infants and Children (WIC) distributes cash vouchers to low-income women with children to buy fruits and vegetables. The program reaches almost half of the infants and one-quarter of children under 5 years old in the United States. UC Cooperative Extension (UCCE) conducted a survey of produce preferences and buying habits among WIC participants in Tulare, Alameda and Riverside counties in 2010 to guide the development of a farm-to-WIC program that would connect small local growers to the WIC market. Based on the results, the UCCE team developed a list of 19 produce items to promote in a possible new farm-to-WIC program

Tomatillo Production in California

Basic information for commercial growers, including climatic requirements, varieties, planting, fertilization, harvest, and marketing channels

Nondestructive maturity determination in green tomatoes using a handheld visible and near infrared instrument

a b s t r a c t A nondestructive method based on visible and near infrared spectroscopy, was investigated for determining the maturity of green tomatoes at harvest. The interactance spectrum of tomato fruit at the firm green stage were measured in less than 5 s with a handheld spectrometer (400-1000 nm) utilizing an optical design with a 0 • angle between the incident illumination and the detection view. Results showed that the predominant change in the interactance spectra in green tomatoes useful for predicting changing maturity levels occurred in the 600-750 nm portion of the 400-1000 nm region, typically associated with chlorophyll. Variety-specific Bayesian classification models and a joint variety 'global' classification model were developed to predict tomato maturity after 7 d of storage in a 20 • C ripening room using canonical discriminant analysis techniques applied to the interactance spectra from 600 nm to 750 nm. Variety specific models correctly identified 75-85% of immature tomatoes and 82-86% of mature green tomatoes in internal cross-validation, however external validation performance decreased when applied to predict maturities in a cultivar external to the training set. False positive rates of these models in identifying immature and mature green tomatoes varied from 3% to 40% and 0% to 31% respectively. A 'global' model, trained on two cultivars showed more stability and correctly predicted 71% of immature and 85% of mature green tomatoes, with false positive error rates of 13% and 22%, respectively, in internal cross-validation of both varieties. This handheld system showed good potential as a rapid, nondestructive technique to aid tomato production managers in the identification of immature green tomatoes at harvest and could be a valuable tool in delivering more flavorful fruit to consumers by reducing the amount of immature fruit harvested by workers

Sweetpotato Production in California

Basic information for commercial growers, including climatic requirements, varieties, planting, fertilization, harvest, and marketing channels

Integrative analysis of postharvest chilling injury in cherry tomato fruit reveals contrapuntal spatio-temporal responses to ripening and cold stress.

Postharvest chilling injury (PCI) reduces fruit quality and shelf-life in tomato (Solanum lycopersicum L.). PCI has been traditionally studied in the pericarp, however its development is likely heterogeneous in different fruit tissues. To gain insight into PCI's spatio-temporal development, we used postharvest biomarkers e.g. respiration and ethylene rates, ion leakage etc., to confirm the occurrence of PCI, and compared these data with molecular (gene expression), biophysical (MRI data) and biochemical parameters (Malondialdehyde (MDA) and starch content) from the pericarp or columella. Tissues were stored at control (12.5 °C) or PCI-inducing temperatures (2.5 or 5 °C) followed by rewarming at 20 °C. MRI and ion leakage revealed that cold irreversibly impairs ripening-associated membrane liquefaction; MRI also showed that the internal and external fruit tissues responded differently to cold. MDA and especially starch contents, were affected by chilling in a tissue-specific manner. The expression of the six genes studied: ACO1 and ACS2 (ripening), CBF1 (cold response), DHN, AOX1a and LoxB (stress-related) showed non-overlapping temporal and spatially-specific responses. Overall, the data highlighted the interconnectedness of fruit cold response and ripening, and showed how cold stress reconfigures the latter. They further underscored that multidimensional spatial and temporal biological studies are needed to develop effective solutions to PCI

Integrative analysis of postharvest chilling injury in cherry tomato fruit reveals contrapuntal spatio-temporal responses to ripening and cold stress.

Postharvest chilling injury (PCI) reduces fruit quality and shelf-life in tomato (Solanum lycopersicum L.). PCI has been traditionally studied in the pericarp, however its development is likely heterogeneous in different fruit tissues. To gain insight into PCI's spatio-temporal development, we used postharvest biomarkers e.g. respiration and ethylene rates, ion leakage etc., to confirm the occurrence of PCI, and compared these data with molecular (gene expression), biophysical (MRI data) and biochemical parameters (Malondialdehyde (MDA) and starch content) from the pericarp or columella. Tissues were stored at control (12.5 °C) or PCI-inducing temperatures (2.5 or 5 °C) followed by rewarming at 20 °C. MRI and ion leakage revealed that cold irreversibly impairs ripening-associated membrane liquefaction; MRI also showed that the internal and external fruit tissues responded differently to cold. MDA and especially starch contents, were affected by chilling in a tissue-specific manner. The expression of the six genes studied: ACO1 and ACS2 (ripening), CBF1 (cold response), DHN, AOX1a and LoxB (stress-related) showed non-overlapping temporal and spatially-specific responses. Overall, the data highlighted the interconnectedness of fruit cold response and ripening, and showed how cold stress reconfigures the latter. They further underscored that multidimensional spatial and temporal biological studies are needed to develop effective solutions to PCI

Cultivar mixtures of processing tomato in an organic agroecosystem

At an organic farm in California, managed biodiversity was manipulated by establishing a mustard cover crop (MCC) and fallow during winter, and after incorporation, tomato mixtures of one, three, and five cultivars were planted in the spring (1-cv, 3-cv, and 5-cv, respectively). It was hypothesized that cultivar mixtures may increase yields over a monoculture if disease pressure or nitrogen (N) availability is affected by the previous cover crop. The monoculture (1-cv) of the grower’s preferred cultivar was compared with mixtures of it and other high-yielding cultivars in the region. Soil nitrogen, soil microbial biomass carbon (MBC), soil emissions of carbon dioxide (CO2) and nitrous oxide (N2O), crop nutrient uptake, biomass, fruit quality, intercepted photosynthetically active radiation (PAR), and disease symptoms were measured. The MCC reduced soil N leaching potential during winter and immobilized soil N early in the tomato season as suggested by higher soil MBC and CO2 emissions. Tomatoes had higher PAR, aboveground biomass, fruit yields, and harvest index in the winter fallow than in the winter MCC, likely due to higher N availability in the fallow plots after transplanting. All cultivar mixtures had fairly similar yield and shoot biomass within fallow and MCC, probably explained by the low genetic diversity among California modern tomato cultivars. However, at mid-season (75 days after planting (DAP)), the 3-cv mixture had higher shoot and fruit biomass, by 46% and 63%, than the monoculture in the MCC, indicating some plasticity under lower N availability. In the fallow treatment, soil CO2 emissions were lower in the 3-cv mixture than the monoculture at 77 and 100 DAP. Tomatoes in the 3-cv mixture were redder than the monoculture. The 3-cv mixture thus had some minor advantages compared with the monoculture, but overall, there was little evidence of higher ecosystem functions from mixtures vs. monoculture. Further research on mixtures of processing tomatoes may only be warranted for conditions of higher environmental stress than occur in California organic farms or if specific genotypic traits become available such as for disease resistance or improved nutrient uptake

Garlic in clay loam soil thrives on little irrigation

We conducted 4 years of irrigation experiments in garlic on the West Side of the San Joaquin Valley to determine appropriate irrigation frequency and cutoff dates as well as the effect of irrigation on yields for crops grown in sandy and clay loam soil. In sandy soil with the moisture content at field capacity prior to the rapid growth stage, yield was strongly dependent on applied water, and weekly irrigation was needed for maximum yield. In clay loam, yield did not depend on applied water because the garlic plants were able to extract sufficient soil moisture to offset deficit irrigation. Irrigation cutoff in both soils should occur by mid-May