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.

Silverleaf is an important fungal trunk disease of fruit crops, such as Japanese plum (Prunus salicina). It is known that infection by Chondrostereum purpureum results in discolored wood, “silvered” foliage, and tree decline. However, effects on fruit yield and quality have not been assessed. Therefore, the objectives of this study were to determine C. purpureum pathogenicity on P. salicina and the effects on physiology, fruit yield, and quality, in Chile, in 2019 and 2020. Wood samples from affected plum trees were collected in the Chilean plum productive area. Fungi were isolated by plating wood sections from the necrosis margin on culture media. Morphological and molecular characteristics of the isolates corresponded to C. purpureum (98%). Representative isolates were inoculated from healthy plum plants and after 65-d incubation, wood necrotic lesions and silver leaves were visible. Fungi were reisolated, fulfilling Koch’s postulates. To determine Silverleaf effects, xylem water potential and fruit yield and quality were measured in healthy and Silverleaf-diseased plum trees ‘Angeleno’. Water potential was altered in diseased trees, and fruit yield was reduced by 51% (2019) and by 41% (2020) compared to fruit from healthy trees. Moreover, cover-colour, equatorial-diameter, and weight were reduced, and fruit were softer, failing to meet the criteria to be properly commercialized and exported to demanding markets.

Silverleaf is caused by the fungus Chondrostereum purpureum, which produces wood necrosis and foliar silvering in woody plants. Field observations and studies in apple have shown the reversion of foliar symptoms. Since plants were clones and received identical agronomical management, it was hypothesized that reversion is driven by endophytic microbiota. Thus, the objectives of this study were to compare healthy, diseased and reverted plants with respect to their physiology, endophytic microbial communities, antagonistic ability of their endophytes against C. purpureum and defense-genes-expression. Water-potential, stomatal-conductance, chlorophyll-content and fluorescence were measured. Endophytic bacterial and fungal DNA were analyzed by DGGE, and communities richness and similarity were calculated. Wood cores were collected and bacterial and fungal endophytes were isolated and confronted with C. purpureum virulent strains in dual-culture assays. Defense-genes-expression were measured by qPCR. Results indicated that there were no differences in physiological parameters between healthy and reverted plants, except for fluorescence, and both type of plants differed from diseased ones. Bacterial and fungal communities richness were similar in healthy and reverted plants, and higher than in diseased ones. Endophytes from reverted and healthy plants showed high antagonism to C. purpureum. Furthermore, NPR1-gene-expression was upregulated in reverted plants, while PAL and PGIP showed higher values in diseased plants. Overall, physiological, molecular and microbial characteristics were similar between healthy and reverted plants, and both differed from diseased ones. Therefore, reversion of symptoms is associated with changes in the endophytic microbiota, which seems to be a promising source of biological control agents against C. purpureum.

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.

El Niño–Southern Oscillation (ENSO) has been identified as a key factor influencing grapevine phenology and harvest timing in South America. Nevertheless, few long-term analyses have explored its varietal impacts in hyper-arid viticultural regions. The goal was to evaluate the effect of ENSO phases on harvest dates and bioclimatic indices in different grapevine varieties cultivated in Northern Chile. The results revealed that Muscat of Alexandria showed little variation in harvest timing across ENSO phases. In contrast, harvest time in Thompson Seedless was delayed under La Niña events, being strongly correlated with the Maximum Spring Temperature Summation (SON_max) Index. Moscatel Rosada and Flame Seedless showed non-statistical significance and high variability on harvest dates. El Niño phases were consistently warmer than La Niña events that showed markedly greater interannual variability on harvest dates and bioclimatic index values. The strength of correlations was improved when the bioclimatic indices were recalculated over adjusted seasonal windows, underscoring the need for phenology-based rather than calendar-based approaches. These results provide new evidence of the heterogeneous responses of table and Pisco grapevine varieties to ENSO events in the hyper-arid regions of Northern Chile, underscoring the varietal differences in sensitivity to early-season climatic anomalies.