Chile is characterized by offering high-quality vitivinicultural products and for its renowned viticultural valleys. At today, Chile has been considered vulnerable to climate change, which has brought a major concern to the national vitiviniculture. This research aimed to analyze the trends and climatic variability of the Chilean viticulture over three decades (1985-2015), evaluating meteorological, bioclimatic and risk indices in forty-seven stations. Meteorological data indicated that the warmest zone was Atacama, while the coldest was Aysén. The rainiest region was Austral, while the driest was Arica y Parinacota. Growing-season indices (GST, GDD and HI) showed that Central Valley was warmer than Arica y Parinacota, whereas, this latter, presented higher sum of spring temperatures (SONMean and SONMax). Atacama presented the highest risk for T>30°C, whereas Central and South Valleys for T>35°C. The highest frost risk was in Aysén, while the lowest in Arica y Parinacota. In general, Min T decreased by 0.33 ºC, while Max T increased by 0.83ºC. None of the trends for PP presented statistical significance. GST, GDD, HI, BEDD, SONMean and SONMax increased by 0.58ºC, 118.29 heat units, 140.57 heat units, 79.72 heat units, 8.42 heat units and 45.17 heat units, respectively, while CI decreased by 0.19ºC. Some stations that presented negative trend on CI coincided to the highest Max T. Locations in Coquimbo and Aconcagua valleys changed from intermediate to warm climate. Locations from Coquimbo and Central valleys changed from warm to hot climate. Quilaco changed from cool to warm climate, while Osorno changed from without classification to cool climate. PCA analysis reported that meteorological variables were related to the distance of the site to the Pacific Ocean. This information is of importance for the national industry and may allow to define mitigations strategies facing global warming.

The growth and development of green lettuce plants can be modulated by the prevailing light conditions around them. The aim of this study was to evaluate the effect of ambient light enrichment with different LED light spectra on agronomic characteristics, polyphenol concentration and relative gene expression of enzymes associated with polyphenol formation in ‘Levistro’ lettuce grown hydroponically in a Nutrient Film Technique (NFT) system for 28 days in a greenhouse. The spectra (blue:green:red:far-red) and red:blue (R:B) ratios obtained by enriching ambient light with Blue (B), White (W), Blue-Red (BR) and Red (R) LED light were B: 47:22:21:10, 0.5:1; W: 30:38:23:9, 0.8:1; BR: 33:15:44:8, 1.3:1 and R: 16:16:60:8, 3.8:1, respectively, and photosynthetically active radiation (PAR) under the different treatments, measured at midday, ranged from 328 to 336 µmoles m⁻² s⁻¹. The resulting daily light integral (DLI) was between 9.1 and 9.6 mol m⁻² day⁻¹. The photoperiod for all enrichment treatments was 12 h of light. The control was ambient greenhouse light (25:30:30:15; R:B = 1.2:1; PAR = 702 µmoles m⁻² s⁻¹; DLI = 16.9 mol m⁻² day⁻¹; photoperiod = 14.2 h of light). Fresh weight (FW) and dried weight percentage (DWP) were similar among the enrichment treatments and the control. The leaf number increased significantly under BR and R compared to B lights. The relative index of chlorophyll concentration (RIC) increased as plants grew and was similar among the enrichment treatments and the control. On the other hand, the concentration of chlorogenic acid and chicoric acid increased under BR and B lights, which was consistent with the higher relative expression of the coumarate 3-hydroxylase enzyme gene. In view of the results, it is inferred that half of the PAR or DLI is sufficient to achieve normal growth and development of ‘Levistro’ lettuce plants, suggesting a more efficient use of light energy under the light enrichment treatments. On the other hand, the blue and combined blue-red lights promoted the accumulation of phenolic compounds in the leaves of ‘Levistro’ lettuce plants.

The use of extended light spectra, including UV-A, green, and far-red, has been scarcely explored in vertical farming. This study evaluated the effects of full spectra under two intensities (90 and 180 µmol m⁻² s⁻¹) on the growth and antioxidant properties of green and purple leaf lettuce. Three light spectra were tested: Blue-White (BW), Red-White (RW), and Red-Blue (RB). Fresh weight (FW), dry weight percentage (DWP), chlorophyll concentration (NDVI), and antioxidant parameters (total phenolic content (TPC), antioxidant capacity by DPPH and FRAP and total flavonoid content (TFC)) were assessed. Spectrum-intensity interactions significantly influenced FW, with RW-180 µmol m⁻² s⁻¹ yielding the highest FW (78.2 g plant⁻¹ in green and 48.5 g plant⁻¹ in purple lettuce). BW-90 µmol m⁻² s⁻¹ maximized DWP in green lettuce, while PAR intensity of 180 µmol m⁻² s⁻¹ favored DWP in purple lettuce. Chlorophyll concentration increased under PAR intensity of 180 µmol m⁻² s⁻¹, and leaf color varied with spectrum, with RW producing lighter leaves. Antioxidant parameters declined over time, but a PAR intensity of 180 µmol m⁻² s⁻¹, particularly under RW, boosted TPC and TFC contents in both lettuce cultivars during early stages (days 0 and 15). Conversely, a lower PAR intensity of 90 µmol m⁻² s⁻¹, mainly under RW, enhanced antioxidant capacity by FRAP at 15 days and by the end of the cycle for both cultivars. Overall, RW-180 µmol m⁻² s⁻¹ interactions promoted the best characteristics in lettuce. Nonetheless, the findings emphasize the significance of fine-tuning both light spectrum and intensity to enhance lettuce growth and quality in vertical farming systems considering the cultivar, time and variable to be evaluated.

Preharvest climatic conditions and irrigation management are decisive determinants of avocado postharvest performance. Avocado trees are highly susceptible to the water regimen, conditions that disrupt carbon assimilation, mineral nutrient uptake, and biomass partitioning. This study evaluated the effects of deficit irrigation imposed during early stages of fruit growth, coinciding with active cell division, on fruit development and postharvest quality of ‘Hass’ avocado. Deficit and excess irrigation induced physiological stress, reducing stem water potential (≈−1 MPa) and altering photochemical efficiency, while F_V/F_M remained unaffected. Fruit growth was strongly affected, with weight reductions of up to 26% during development and 22% at harvest under severe deficit, resulting in fruits becoming more yellowish-green. In contrast, excessive irrigation promoted larger fruit with darker green skin, with delayed maturation. Metabolomic revealed that the fruit developmental stage was the main driver of metabolic variation, while irrigation effects were minor and stage-dependent, limited to osmotic-related metabolites such as GABA. These findings indicate that early-season water imbalances primarily affect fruit growth through changes in water relations rather than metabolic reprogramming, highlighting the importance of precise irrigation management during critical developmental stages. Fine-tuning water supply during early developmental stages is a strategic tool for optimizing fruit size and postharvest quality in avocado.

La calidad y producción de la vid dependen del clima; por lo tanto, los cambios en éste pueden afectar su sustentabilidad. Para Chile, se ha proyectado un incremento de las temperaturas en el Valle Central de al menos 1 ºC, lo que puede afectar directamente el proceso de maduración de vid, acelerando la acumulación de azúcares, afectando los ácidos orgánicos y disminuye los compuestos fenólicos, lo que se traduce en un desequilibro de la maduración. Considerando esto, para asegurar la sustentabilidad de la viticultura frente al cambio climático, se buscan alternativas de manejo que permitan una óptima maduración frente a las condiciones climáticas cambiantes. Una de estas alternativas es la poda tardía. La poda tardía, propone retrasar las fechas de poda posterior a la brotación y previo a la floración, eliminando las reservas ya movilizadas en la planta, generando con esto un retraso fenológico. Este retraso en el crecimiento permitiría una maduración menos acelerada. Para evaluar la efectividad de esta técnica, durante la temporada 2020-2021 en un viñedo comercial del cv Cabernet Sauvingnon en el Valle Central se evaluaron tres fechas de poda: poda tradicional (PT), poda en brotación (PB) y poda en 2-3 hojas (PH). Los resultados preliminares de este estudio, muestra expectativas positivas de esta técnica retrasando la fenología del cultivo y las fechas de cosecha. Sin embargo, esto parece depender del momento fenológico donde se realiza la poda tardía y las características varietales. La PB presentó un retraso del momento de cosecha de seis días, sin afectar la producción o la calidad inicial de las bayas. Asimismo, el PH afectó el cuajado de los racimos y no retrasó la cosecha. Los resultados mostraron que es posible retrasar las fechas de cosecha; sin embargo, es relevante considerar otras variables como la variedad, momento fenológico, suelo y clima.

Potassium (K) is an essential macronutrient that plays a central role in grapevine physiology and fruit quality. This study aimed to evaluate the effects of different K concentrations in the nutrient solution on berry composition, color development, and mineral concentration in leaves, petioles, and berries of fruit-bearing cuttings of Vitis vinifera L. cv. Tempranillo. Fruit-bearing cuttings were grown under controlled greenhouse conditions and irrigated with modified half-strength Hoagland solutions containing 0%, 25%, 50%, 75%, or 100% K and a control nutrient solution. Berry quality parameters, including total soluble solids, acidity, anthocyanins, and phenolic maturity, were significantly influenced by K availability. Moderate K treatments (50–75%) produced the most favorable outcomes in terms of sugar accumulation, anthocyanin concentration, and nutrient balance. The results suggest that optimized K fertilization is critical for improving grape quality while avoiding potential negative effects associated with deficiency or excess. These findings provide valuable insights for K management in viticulture.