Handroanthus chrysanthus and Swietenia macrophylla are ecologically and economically significant tree species whose populations have declined due to high demand for their timber, adversely affecting their natural regeneration. This study aimed to evaluate the ecophysiological response to increased photosynthetic photon flux density (PPFD) in H. chrysanthus and S. macrophylla seedlings under Amazonian conditions. Assimilation measurements (A) were performed using a portable iFL-LCpro-SD system. The evaluation of A in response to increased PPFD ranged from 25 to 1800 μmol m⁻²s⁻¹. Water use efficiency (WUE) was calculated as the ratio between A and the transpiration rate (E). S. macrophylla exhibited a significantly higher maximum photosynthetic assimilation rate (Amax, 9.4 ± 0.52 µmol CO₂ m⁻² s⁻¹) compared to H. chrysanthus (6.18 ± 0.17 µmol CO₂ m⁻² s⁻¹, p < 0.05), indicating greater carbon fixation efficiency. S. macrophylla showed a maximum WUE (WUEmax) of 13.17 ± 0.24 µmol mmol⁻¹ at 600 μmol m⁻² s⁻¹ PPFD, while H. chrysanthus reached its WUEmax (6.16 ± 0.23 µmol mmol⁻¹) at 750 μmol m⁻² s⁻¹ PPFD. These results suggest that S. macrophylla exhibits higher WUE under high irradiance conditions, potentially due to more efficient stomatal regulation and an optimized balance between carbon fixation and water loss via transpiration.

The global production of pecan nuts (Carya illinoinensis) is expanding, generating growing interest in the valorization of their by-products, particularly the shell, a promising source of bioactive compounds and natural antioxidants. To support its use in food, nutraceutical, and pharmaceutical applications, optimizing extraction conditions is essential. In this study, pecan shells were dried, ground, and sieved into three particle sizes: coarse (250-150 µm), medium (150-100 µm), and fine (≤100 µm). Phenolic compounds were extracted using an ultrasonic bath, and total phenolics were quantified by the Folin-Ciocalteu method. Reducing power and the ability of the extracts to scavenge DPPH and ABTS radicals were also assessed. LC-MS/MS was used to characterize the most efficient extract. Fine particles produced higher extract yields, while medium and fine particles resulted in greater total phenolic content. Twelve phenolic compounds were identified, including the flavonoids gallocatechin 3-O-gallate, catechin, gallocatechin, procyanidin C1, procyanidin B1, isorhamnetin 3-glucuronide, and taxifolin 3-O-rhamnoside, as well as methyl chlorogenate, gallic acid 3-O-gallate, and 3-caffeoylquinic acid. Antioxidant activity increased with particle size reduction down to 100 µm, but smaller sizes reduced this activity. Extracts obtained from medium particles showed the highest phenolic content (20.52 ± 0.08 mg GAE/g) and antioxidant activity (58.81 ± 0.80% for DPPH and 79.00 ± 0.96% for ABTS). These findings provide valuable insights into optimizing phenolic extraction from pecan shells for applications in food and health-related industries.

The objective of this study was to evaluate the production and quality of fruits from four of the most common pecan cultivars in Brazilian orchards, under the edaphoclimatic conditions of the Northwestern region of Rio Grande do Sul, Brazil. The experiment was conducted in the municipality of Santa Rosa during the 2020/2021 and 2021/2022 harvests. A completely randomized experimental design was used, with plants of 13 years of age from four cultivars: Barton, Pitol 1, Shawnee, and Success, with seven replications per cultivar. The following parameters were evaluated: productivity (kg per hectare), fruit and kernel length and diameter, shell thickness, fruit and component mass, kernel yield, color and luminosity of kernels, and percentage of commercial kernels. The cultivars Success (975.41 kg·ha-1), Barton (951.02 kg·ha-1), and Pitol 1 (938.04 kg·ha-1) showed higher average productivity compared to the Shawnee cultivar (689.23 kg·ha-1). The fruits of the Pitol 1 cultivar stood out for their larger size and mass, requiring approximately 30 fewer fruits per kilogram compared to the Barton and Shawnee cultivars, and 25 fewer compared to Success. In terms of kernel quality, Barton produced more yellowish fruits, while Success had a lower percentage of commercial kernels compared to Barton, Pitol 1, and Shawnee. Based on these results, due to reconciling higher productivity with fruit quality variables, Success, Barton, and Pitol 1 are the most recommended cultivars for cultivation under the edaphoclimatic conditions of Northwestern Rio Grande do Sul.

The cultivation of pecan has been expanding in Uruguay for over 10 years. Given the lack of knowledge about its management and behavior under local conditions, the objective was to evaluate the viability and productive potential of different pecan cultivars, identifying those best suited to our soil and climate conditions. In 2010, a trial garden with 18 cultivars was established at INIA Las Brujas. The study assessed plant vigor, precocity, and yield (kg/plant) over nine consecutive harvests, along with phenology, and nut quality. The cultivars that have shown good productive performance are Oconee, Kiowa, Nacono and Success, in combination with Pawnee and Cape Fear to improve pollination, as these two cultivars exhibited protandry, while the first four exhibited protogyny. The flowering period occurred from late October to late November. The cultivars that demonstrated the fastest entry into production were Kiowa, Success, Oconee, Cape Fear, and Apache. This study represents the first evaluation of pecan cultivars conducted in the country, providing valuable information on their agronomic performance and aiding decision-making regarding which cultivars to plant under southern Uruguayan soil and climate conditions.

Edaphoclimatic zoning for walnut trees is a modeling of climate and soil properties for favorable planting conditions. The evaluated areas as Preferential class, Recommended class and Few Recommended, fertility-only restricted class occupied 236 ha or 0.04% of total territory, 49,207 ha or 8.5%, and 146,074 ha or 12.7%, respectively. That is almost 120 times the planting area of pecan orchards, with 1,652 hectares. Thus, there is a significant potential for pecan production in the region. Rio Grande do Sul is the most favored state with 42,832 ha of recommended areas, for varieties of 200-300 chilling hours or 300-500 chilling hours, followed by Parana and Santa Catarina states, both with 1,056 ha. While Parana concentrates 1,045 ha as recommended aptitude for varieties of 300-500 chilling hours, Santa Catarina has a somewhat more balanced distribution. These states have more areas of “Few Recommended, fertility-only restricted” class, whose aptitude is adequate in all properties as recommended class, except for fertility, which is a property easy to adjust at field, incorporating inputs. Southern Brazil region covers 576,257 km2, 35% correspond to Preferential, Recommended and Few Recommended areas, 61.5% of territory is related to not recommended or restricted areas, 3% represent body waters, and 0.5% are urban areas.

Pecan, native to the United States and Mexico, has attracted growing global interest as a health-promoting food, particularly in Argentina, where the province of Catamarca stands out for its favorable agroclimatic conditions. This study evaluated the yield and nut quality of eight pecan cultivars (‘Stuart’, ‘Pawnee’, ‘Mahan’, ‘Shoshoni’, ‘Western’, ‘Wichita’, ‘Kiowa’, and ‘Desirable’) in the arid region of the Catamarca province, Argentina. Yield, physical traits (nut weight, size, and kernel percentage), external and internal quality, oil content, and fatty acid composition were analyzed. ‘Shoshoni’ was the most productive cultivar, with >17 kg plant-1 accumulated (2018-2024), while ‘Mahan’ showed the highest nut and kernel weight. ‘Wichita’, ‘Pawnee’, and ‘Mahan’ exhibited the highest edible kernel percentages (>55%). Regarding external quality, ‘Wichita’, ‘Pawnee’, and ‘Western’ showed minimal damage. For internal quality, ‘Wichita’, ‘Kiowa’, ‘Western’, and ‘Desirable’ presented the highest percentages of edible kernel (97%). Fatty acid composition varied significantly among cultivars, with ‘Desirable’ showing high oleic acid content, while ‘Western’ and ‘Wichita’ stood out for their linoleic acid content. The results confirm the viability of pecan cultivation in Argentina’s arid regions, highlighting the importance of selecting well-adapted cultivars and implementing proper management practices to optimize nut yield and quality.

The objective of this study was to evaluate the main yield components and quality attributes of four pecan cultivars. The experiment was conducted in a commercial orchard in the municipality of Francisco Beltrão, Paraná State, Brazil. Eight- and nine-year-old plants, spaced 10m x 9m apart, of the cultivars Barton, Imperial, Pitol 1 (Melhorada) and Pitol 2 (Importada) were evaluated over two agricultural seasons (2018/2019 and 2019/2020). The nuts were harvested using a Shaker-mak harvester attached to a tractor. After harvest, the fruits were left to dry in full sun for seven days. The number of nuts per plant and nut production (kg) were evaluated, and the productivity estimate (kg·ha-1) was obtained. From samples of 20 nuts per plant, the fresh nut mass (g), nut yield (%), diameter (mm), and length (mm) were measured. Samples of 10 nuts per plant were subjected to a breaking force test (N) to simulate the ease or difficulty of shelling. Under the soil and climatic conditions of Southwest Paraná, it was concluded that: the Barton cultivar was the most productive (12.4 kg·plant-1 = 1,376 kg·ha-1); the Imperial produced the largest nuts (9.1 g); the average nut yield of the evaluated cultivars was 47.8%; and the Imperial cultivar exhibited greater resistance to shell rupture.

Pecan cultivation is growing in Brazil, especially in Rio Grande do Sul, which is currently the country's leading producer. The demand for qualified technical information about the production chain has been increasing considerably. The Pecan Cultivation in Rio Grande do Sul Diagnosis project was created in this context, with the objective of characterizing the management of orchards, as well as identifying difficulties and possibilities for improvement, by conducting interviews with pecan producers. The sample size was calculated by determining the size of a sample for a finite population based on the estimated proportion in each municipality, which defined 319 interviews. The results show that 63% of the orchards are up to 4 hectares in size; the most common spacing is 10m x 10m; the average productivity was 1105.48 kg·ha-1 in the 2023 harvest; 34% of the producers do not have technical assistance for walnut trees; approximately 30% did not correct the acidity, phosphorus and potassium of the soils before establishing the orchard; almost 80% of the orchards are managed conventionally; less than 10% have irrigation. Regional analysis of pecan orchard management practices revealed significant disparities among then. The main pests and diseases are ants, anthracnose and scab. Manual harvesting is used on 63%. For farmers, the main difficulties in developing the pecan cultivation are: the time between planting and production, the low productivity of the orchard and the price paid.

En pecán, el área de proyección de copa (APC), el diámetro de tronco (DBH) y la altura del árbol (H) son componentes de la arquitectura arbórea que interactúan entre sí y con el suelo. El objetivo de este trabajo fue validar si las relaciones funcionales de la arquitectura arbórea a nivel intraárbol y su interrelación con los recursos edáficos (carbono orgánico del suelo [COS] y zinc [Zn]) observadas en otras plantaciones frutales ocurren también en una plantación de pecán bajo las condiciones edafoclimáticas específicas del sudeste de la provincia de Buenos Aires, Argentina. Para ello se determinaron: el APC mediante fotogrametría utilizando un dron mini, COS, nitratos, amonio y Zn en suelo (0-20 cm de profundidad) e indicadores dasométricos (DBH, altura), medidos con cinta métrica y regla telescópica. Las determinaciones se realizaron durante el mes de abril (coincidiendo con el momento del fin del llenado de la nuez) durante los años 2022, 2023 y 2024 en una plantación multicultivar ubicada en la EEA INTA Balcarce (37,76º S, 58,29º O). Se encontraron correlaciones positivas para APC vs. DBH, DBH vs. H, y APC vs. H (en todos los casos, p<0,001), APC vs. COS (r=0,63, p=0,001) (2022, 2023 y 2024), y para la concentración de Zn vs. APC (r=0,54, p=0,03) (2022 y 2023). Nuestros resultados indican que los parámetros medidos intraplanta (APC, DBH y H) se retroalimentan positivamente, pero la variable más asociada a los recursos disponibles que se encuentren en el suelo es el APC.