Scion-rootstock combination influences nut yield and quality in a super high-density almond orchard in the...

Super high-density (SHD) almond planting systems have emerged to improve sustainability through more efficient use of natural resources. These systems are enabled by self-fertile, late-blooming cultivars and rootstocks of contrasting vigor. To identify optimal scion-rootstock combinations in warm environments, an SHD trial was established with four self-compatible cultivars - 'Belona', 'Lauranne', 'Guara', and 'Tuono' - grafted on vigorous 'Garnem' and dwarfing 'Rootpac40' (R40) rootstocks. Nut yield and quality were assessed over 5 years and analyzed alongside previously reported eco-physiological and nutritional parameters.

'Rootpac40' induced the highest overall yield and yield efficiency, particularly with 'Lauranne' and 'Guara', whereas 'Garnem' provided the highest shelling percentage. 'Belona' performed the poorest on both rootstocks. The R40 rootstock consistently promoted beneficial characteristics across all pomological parameters, and 'Lauranne' exhibited the lowest values. 'Belona'-R40 and 'Belona'-'Garnem' produced the largest nuts and the heaviest fruit, whereas 'Lauranne'-'Garnem' resulted in the smallest nuts and kernels. 'Belona' recorded the highest oil and polyphenol content. 'Lauranne' exhibited strong biochemical traits and a suitable fatty acid composition. 'Garnem' increased oil content compared with R40, particularly for 'Belona' and 'Lauranne'. 'Lauranne'-'Garnem' showed the lowest biochemical values and fatty acid content. R40 was associated with the highest overall fatty acid content.

'Lauranne' and 'Guara' on R40 demonstrated good physiological adaptation, high yield, efficient productivity, suitable nut characteristics, and valuable biochemical properties, providing a promising strategy for SHD almond-planting systems in new and challenging warm environments. © 2026 Society of Chemical Industry.