Modern almond growing travels on the tracks of super-high density (SHD). Born in 2010, it has already reached 6700 ha planted all over the world. This new cultivation system needs to define efficient agronomic techniques in order to identify it as a “Super-Efficient System”. Among these, the choice of cultivar is a crucial technique and a key factor for sustainability. The purpose of this study was to compare different cultivars in terms of vegetative, productive, and efficiencies parameters in order to gain applicable relevant knowledge about the SHD almond cultivation technique. For this, 3 years of research was carried out during 2017–2019, on a young almond grove made in 2014 with row spacing of 3.80 m × 1.20 m (2190 trees/ha), to evaluate the agronomic behavior of the two most planted cultivars in Italy, Guara-Tuono and Lauranne^® Avijor, grafted on the Rootpac^®20 dwarfing rootstock. The main biometric, productive, yield, mechanical harvesting efficiencies, and almond quality parameters were evaluated. Cv Lauranne^® showed greater vigor, greater fruit yield, and damaged axes by mechanical harvesting, while higher values of yield efficiencies were observed for cv Tuono. Harvesting efficiency was related to canopy size and tree age. On the contrary, almonds quality parameters were strongly related to the cultivar, confirming the good performance of Tuono as varietal characters. Then, this cultivar seems to be the most suitable for an efficient SHD planting system, in line with the objectives of modern sustainable fruit growing. The better performance of cv Tuono could be related to the positive influence of the terroir as well.

By 2022, the total area of super high-density (SHD) almond orchards worldwide had spread to 14,622 ha. As well as factors such as spacing, and tree architecture, proper row orientation should ensure a more efficient sun exposure, yield and harvesting. This research was conducted in an irrigated SHD almond orchard of cv. Lauranne^® Avijor in Andria, Italy, in 2021 and 2022 (at 4th and 5th year from planting, respectively) to gain a deeper understanding on the effects of two row orientations on available Photosynthetic Active Radiation (PAR), Leaf Area Index (LAI), canopy growth, yield and harvesting efficiencies in this new planting system. The east-west row orientation in a SHD almond orchard negatively impacted LAI, canopy growth, yield, fruit quality and yield efficiencies, especially in the second year. The north-south row orientation allowed a better PAR distribution inside the whole canopy than east-west row orientation. This unevenness in PAR distribution inside the whole east-west oriented canopies could represent the driving engine of the effect on growth and yield parameters. Although some quality parameters differed between exposures, they all remained within the standard range of the cultivar. The results provide a scientific basis for improved SHD orchard management, helping to keep them as Sustainable and Efficient Systems (SES).

Site selection analysis is a fundamental methodology for the regeneration of Xylella fastidiosa subsp. pauca (Xfp) infected areas, with the introduction of Xfp immune/resistant tree crop species. The diffusion of these species could be assessed by combining ecological optima data, climate and soil attributes of the study area, and GIS tools. The study aimed to evaluate the potential suitability of eight Xfp immune tree crops, including Neglected and Underutilized Species (NUS) drought-resistant and new species, as follows: carob, hawthorn, prickly pear, mulberry, loquat, walnut, persimmon, and avocado. The use of GIS tools allowed the integration of different layers, such as climate and soil, to contribute to the identification of suitable areas for the cultivation of these tree crops helping the policy-makers to define plans for land use at a regional scale. Following the ecological optima, which represents the ideal environmental conditions for each species, this analysis provided valuable insights into the compatibility of the selected tree crops with the prevailing environmental factors in the affected area. Carob revealed its remarkable adaptability and drought resistance, presenting the broadest suitability. Hawthorn and Loquat also exhibited high adaptability, indicating their potential contribution to agricultural diversification and ecological balance. Conversely, crops like Avocado, Prickly pear, and Walnut, despite their economic value, demonstrated limited adaptability due to their specific soil and climate requirements. These findings can potentially contribute to the development of strategies for the policy-makers, aimed at diversifying and enhancing the resilience of agricultural systems, facing the problem of emerging quarantine pathogens and the incoming climate change, and highlighting the possibility of opening new cultivation scenarios in the zones affected by Xfp.

Super-high density (SHD) is the latest innovation in almond growing. This new cropping system needs to be studied in different climates, soils, latitudes and cultivars in order to promote more efficient and sustainable orchard management. This study shows the effects of two row orientations and different canopy positions on leaf area index (LAI), photosynthetically active radiation (PAR) and biological, phenological and agronomical parameters of a SHD almond orchard. Total bud number and flower bud number were higher for N-S row orientation and more wood buds were detected in top layers. LAI was strongly influenced by layer, but not by row orientation. Row orientation did not affect blooming or ripening phenology. Fruit number per layer was higher for North–South (N-S) row orientation and in middle layers; fruit set showed the opposite trend to flower bud and fruit numbers, achieving higher values for East–West (E-W) row orientation. Hulled fruit yield was not affected by row orientation but by canopy height. N-S oriented rows showed a greater number of empty nuts than E-W, but no differences were found between layers. We concluded that in SHD almond orchards, row orientation is determinant for sustainable crop management.

This research focuses on the seasonal patterns of the ecophysiological recovery of four olive cultivars (Arbequina, Coratina, Frantoio, and Urano), both micropropagated and self-rooted, grown in a mature, irrigated, super high-density (SHD) orchard under Mediterranean conditions (Southern of Italy). The aim was to observe the impact of the micropropagation method on the ecophysiological responses. Ecophysiological parameters, including leaf water potential (LWP), stomatal conductance (gs), net photosynthetic rate (Pn), and transpiration rate (E) were assessed. Self-rooted trees consistently exhibited superior gs, E, and Pn recovery compared to the micropropagated ones. ‘Arbequina’ maintained elevated levels of Pn under water-deficit conditions. ‘Coratina’ exhibited increases in gs and E after irrigation. ‘Frantoio’ demonstrated recovery capabilities, with lower LWP and higher Pn under stress. ‘Urano’ micropropagated trees achieved higher gs values in mid-summer, while self-rooted trees sustained higher Pn later in the season. This field research highlighted the important role of the propagation method in optimizing the physiological performance of olive cultivars in SHD orchards. Furthermore, it highlighted the necessity of long-term studies on the effects of propagation methods and their interactions with other farming practices.

Introduction: The almond tree is a major global nut crop, and its production has surged dramatically in recent years. Super high-density (SHD) planting systems, designed to optimize resource efficiency and enhance precocity, have gained prominence in almond cultivation. A shift in cropping systems toward sustainable intensification (SI) pathways is imperative, and so maximizing branching density within the canopies of SHD trees is crucial to establish and maintain productive potential, especially for hedge-pruned trees. This study investigates the influence of different almond cultivars grafted onto a novel growth-controlling rootstock on tree architectural and growth parameters in a SHD orchard. This open field research provided valuable insights for the development and application of new tools and methods to increase productivity and sustainability in almond growing.Methods: Three cultivars (Lauranne^® Avijour, Guara Tuono, and Filippo Cea) were evaluated in Gravina in Puglia (BA) over a two-year period. Canopy growth parameters, such as canopy volume and trunk cross-sectional area, and architectural traits, like branching density, branching angle, number and length of subterminal shoots, and number of brachyblasts, were measured through qualitative and quantitative measurements.Results and discussion: Results revealed significant differences in tree height, canopy thickness, width, volume, and vigor among the cultivars. Architectural traits, including branch parameters, brachyblast parameters, and subterminal shoots, varied among the cultivars. Lauranne displayed a more compact well-distributed canopy and exhibited the lowest vigor. Filippo Cea showed the highest vigor and the greatest canopy volume. Tuono had a higher number of buds and bud density. The best ideotype for SHD orchards is a smaller tree, with high branching density and smaller trunk diameters, i.e. the vigor. Cv. Lauranne seemed to be the best cultivar, mostly with the lowest tree vigor of all the cultivars involved. These findings provide valuable insights for almond growers and breeders seeking to optimize orchard design and management for enhanced SHD orchards productivity and sustainability. Future research will explore the relationship between canopy architecture and yield parameters, considering different scion/rootstock combinations in different environmental conditions.