To overcome the environmental changes occurring now and predicted for the future, it is essential that fruit breeders develop cultivars with better physiological performance. During the last few decades, high-throughput plant phenotyping and phenomics have been developed primarily in cereal breeding programs. In this study, plant reflectance, at the level of the leaf, was used to assess several physiological traits in five Vaccinium spp. cultivars growing under four controlled conditions (no-stress, water deficit, heat stress, and combined stress). Two modeling methodologies [Multiple Linear Regression (MLR) and Partial Least Squares (PLS)] with or without (W/O) prior wavelength selection (multicollinearity, genetic algorithms, or in combination) were considered. PLS generated better estimates than MLR, although prior wavelength selection improved MLR predictions. When data from the environments were combined, PLS W/O gave the best assessment for most of the traits, while in individual environments, the results varied according to the trait and methodology considered. The highest validation predictions were obtained for chlorophyll a/b (R²_Val ≤ 0.87), maximum electron transport rate (R²_Val ≤ 0.60), and the irradiance at which the electron transport rate is saturated (R²_Val ≤ 0.59). The results of this study, the first to model modulated chlorophyll fluorescence by reflectance, confirming the potential for implementing this tool in blueberry breeding programs, at least for the estimation of a number of important physiological traits. Additionally, the differential effects of the environment on the spectral signature of each cultivar shows this tool could be directly used to assess their tolerance to specific environments.

Canopy temperature (Tc) by thermal imaging is a useful tool to study plant water status and estimate other crop traits. This work seeks to estimate grain yield (GY) and carbon discrimination (Δ¹³C) from stress degree day (SDD = Tc − air temperature, Ta), considering the effect of a number of environmental variables such as the averages of the maximum vapor pressure deficit (VPDmax) and the ambient temperature (Tmax), and the soil water content (SWC). For this, a set of 384 and a subset of 16 genotypes of spring bread wheat were evaluated in two Mediterranean-climate sites under water stress (WS) and full irrigation (FI) conditions, in 2011 and 2012, and 2014 and 2015, respectively. The relationship between the GY of the 384 wheat genotypes and SDD was negative and highly significant in 2011 (r² = 0.52 to 0.68), but not significant in 2012 (r² = 0.03 to 0.12). Under WS, the average GY, Δ¹³C, and SDD of wheat genotypes growing in ten environments were more associated with changes in VPDmax and Tmax than with the SWC. Therefore, the amount of water available to the plant is not enough information to assume that a particular genotype is experiencing a stress condition.

Chili pepper is produced by family farmers in central Chile incorporating modern technologies and maintaining traditional practices. Although chili pepper is deeply rooted in the local culture, the agricultural system supporting its production and the germplasm involved are poorly studied. This work focused on two main landraces lacking information about what features (agronomic, morphological and chemical) distinguish them and how distinct they are. It is also of high importance to deepen our understanding of the agricultural system and the aspects that may affect its sustainability. An integrated approach was applied for the evaluation of social characteristics of farmers, the growing system, morphological traits, and selected chemical components. Between landraces, flower and fruit morphology was clearly distinct. Total phenolic content, antioxidant capacity and total carotenoid content showed higher values in fruits of cacho de cabra than in chileno negro. Both landraces had a higher total phenolic content than other Capsicum cultivars in the world. Farmers ascribe distinct attributes for the landraces regarding agronomic performance, fruit quality and processing applications. Characteristics that may affect the sustainability of the agricultural system are small farm size, relatives working as employees, and low farmers’ educational attainment. The study landraces are distinct and represent unique genetic material produced in an agricultural system facing important challenges where farmers have adapted to socio-economic pressures, externalizing plant production, reducing harvest costs, and developing innovations in product and marketing.

Chile has become a significant producer of hazelnuts (Corylus avellana L.) due to its favorable conditions for off-season production to meet global market demand. Efficient light interception is crucial for optimizing the hazelnut yield and quality, as it directly influences the plant’s photosynthetic capacity. The goal was to assess the impact of intercepted photosynthetically active radiation (PAR) at upper, middle, and lower canopy levels in hazelnut trees grown at different planting densities and the canopy management of yield and quality parameters. The percentage of vain, sucker, double, bug, and healthy hazelnuts, including the number of fruits, total fruit weight, and grams per fruit was evaluated. The upper canopy levels intercepted the highest PAR, significantly enhancing the number and weight of fruits. The lower canopy levels received considerably less PAR, reducing the productivity. Production pruning in dense planting systems (5 × 3 m) improved the light penetration compared to a less dense planting density (5 × 6 m). Strong positive correlations were observed among PAR, fruit weight, and fruit number, emphasizing the importance of the light distribution within the canopy in hazelnut production. Production pruning and optimized planting densities are essential for maximizing light interception, improving yield, and ensuring high-quality hazelnut production.

In this study, we address the question of the most important factors influencing yield and fruit quality in highbush blueberries. An experiment was carried out to investigate the relationship between yield components and (i) plant yield, (ii) fruit quality traits, and (iii) fruit firmness post-harvest in two Vaccinium corymbosum L. blueberry cultivars (‘Duke’ and ‘Brigitta’). In a field in central Chile (35°15′39″ S; 71°14′32″ W) during the growing season 2018–2019, we measured the number of canes (NC), length of the first shoot (LFS), age of the first shoot (AFS), diameter of the first shoot (DFS), flower buds per cane (FBC), number of one-year shoots per cane (SPC), flowers per bud (FPB), fruit set percentage (FSP), yield (YLD), fruit weight (FW), fruit firmness at harvest (FF), fruit diameter at harvest (FD), soluble solids/acid ratio at harvest (SS:AC), and fruit firmness after harvest (FF_pos). The most important factors affecting yield and fruit quality were FBC, SPC, and FF. Our results suggest that FBC and SPC could be managed agronomically to optimize fruit load and light interception.