Blueberry (Vaccinium corymbosum L.) production under tunnels has spread in recent years. However, there is little information on the productive and physiological responses of blueberry grown under high tunnels. The objective of this research was to evaluate the effect of high tunnel microclimate on the physiological and productive responses of blueberries. A total of 1296 plants of highbush blueberry 'O'Neal' were grown in high tunnels, leaving the same amount of plants under open fields (control). Environmental temperature (T, °C) and relative humidity (RH, %), diffuse and total photosynthetically active radiation (PAR diffuse and PAR total , µmol m -2 s -1 ), stomatal conductance (g s , mmol m -2 s -1) and maximum photochemical efficiency of photosystem II (F v /F m ) of the leaf were measured. Fruit yield, date of harvest initiation and fruit growth rate were also determined. The maximum T was on average 10-12 °C higher inside the high tunnel than the control, whereas the minimum T averaged only 2-5 °C higher. PAR total decreased an average of 25% under tunnel, while levels of PAR diffuse increased more than 150%. The g s ranged between 42% and 99% higher in the high tunnel compared to the control, and was positive and statistically related (r 2 = 0.69**) to PAR diffuse variations. Blueberries under high tunnel recorded an accumulated yield 44% higher, while harvest started 14 d earlier compared to control. The results suggest that high tunnels in blueberries increases fruit yield and improves precocity due to higher temperatures during the flowering stage and fruit set. Particular light conditions under tunnels would favor higher leaf stomatal conductance in this crop.

The Biobío Region in Chile presents special edaphoclimatic characteristics and biodiversity that make it suitable for the introduction and development of some berries that are understudied in terms of their health-promoting composition and characteristics. Chilean strawberry (Fragaria chiloensis ssp. chiloensis, form chiloensis) and calafate (Berberis microphylla G. Forst.) have been underused despite having interesting nutritive values and health-promoting capacities. The polyphenolic compositions of Chilean strawberry and calafate were characterized by HPLC-DAD-ESI-MSn analyses, as well as their antioxidant potential (in ORAC and DPPH assays). The major secondary metabolites present in Chilean strawberry and calafate were ellagic acid derivatives and anthocyanins, respectively, being the anthocyanins more closely related to the higher antioxidant capacity found in the berries. Therefore, the Biobío Region berries analyzed are rich in bioactive phytochemicals with health-promoting characteristics. This represents an opportunity for the food industry and for international trade with Chilean berries, as well as a potential way of promoting rural development in the region.

There is a worldwide increase of heavy metal or potentially toxic element (PTE), contamination in agricultural soils caused mainly by human and industrial action, which leads to food contamination in crops such as in maize. Cadmium (Cd) is a PTE often found in soils and it is ingested through food. It is necessary to determine the bioabsorption, distribution, and accumulation levels in maize to reduce or prevent food chain contamination. Cadmium absorption and accumulation in three maize cultivars were evaluated in three agricultural environments in Chile by increasing CdCl2 rates (0, 1, and 2 mg·kg−1). Evaluation included Cd accumulation and distribution in different plant tissues, bioaccumulation factor (BAF), bioconcentration factor (BCF), translocation factor (TF), and tolerance index (TI). Cadmium whole-plant uptake was only affected by the CdCl2 rate; the highest uptake was obtained with 2 mg·kg−1 CdCl2 (34.4 g·ha−1) (p < 0.05). Cadmium distribution in the maize plant usually exhibited the highest accumulation in the straw (p < 0.05), independently of the environment, Cd rate, and evaluated cultivar. Given the results for TF (TF > 2) and BAF (BAF > 1), the Los Tilos and Chillán environments were classified as having a high capacity to contaminate the food chain for all evaluated cultivars.

Blueberry production under netting has increased in recent years to mitigate the adverse effects of climate change. The objective of the present study was to evaluate the effect of different radiation intensities on rabbit-eye blueberry (Vaccinium virgatum Aiton) 'Ochlockonee' photosynthetic efficiency and productive parameters. Four treatments were established: T1 (control), T2, T3, and T4 at 0%, 30%, 60%, and 90% radiation decrease (RD), respectively, with black shedding netting. The following were recorded for each treatment: environmental conditions, photosystem II (PSII) maximum quantum yield (F v /F m ), photosystem II effective quantum yield (Φ PSII ), leaf stomatal conductance (g s ), quality parameters, and fruit yield. Results showed an increase of 4.6 ºC in mean minimum temperatures for the different netting treatments, which promote development and fruit set, as well as prevent damage at temperatures near 0 ºC. The RD treatments increased Φ PSII between 175% and 325% (P < 0.05) compared to the control. It can be concluded that netting decreased soil temperature between 1 and 3 ºC and increased minimum temperatures between 1 and 6 ºC, which promoted plant development and decreased frost damage during flowering and fruit development. Current direct radiation levels over 1000 µmol m -2 s -1 in V. virgatum inhibited productivity in T1. Netting decreased the degree of photoinhibition and increased photosystem II photochemical efficiency throughout the day, and T4 and T3 exhibited the highest efficiency. K e y w o r d s : P h o t o s y s t e m I I , p h o t o i n h i b i t i o n ,photosynthetically active radiation, stomatal conductance.