Chemical Fingerprint and Kernel Quality Assessment in Different Grafting Combinations of Almond Under Stress Condition

•Drough stress affect on lower quality of almond kernel.•‘GF 677’ had a better response to drought stress than Myrobalan plum.•Drought tolerance was related to higher flavonoid accumulation.•Water deficit can be decreased with appropriate graft combination. The study was designed to investigate chemical composition and kernel quality of almond cultivars ‘Troito’, ‘Marcona’ and ‘Texas’ grafted on Myrobalan plum seedlings and ‘GF 677’ rootstock under drought stress. Oil content varied from 53.34% (‘Marcona’) to 58.11% (‘Texas’), and protein content was in a range from 17.36% (‘Texas’) to 23.02% (‘Troito’). ‘GF 677’ contributed to a higher content of oleic and lower content of linoleic acid during favourable conditions but had the opposite trend during drought. Regarding flavanols, the most abundant in all three cultivars was epigalocatechin, followed by catechin. From the results it is concluded that scions on ‘GF 677’ were better adapted to water stress conditions in comparison with Myrobalan plum seedlings as they had significantly higher kernel weight, kernel ratio, and yield per tree. Also, kernel quality attributes, contents of proteins, oleic acid, and oleic acid/linoleic acid ratio were higher, while the content of amandin decreased. Furthermore, an increase of flavanols (especially epigallocatechin gallate) on ‘GF 677’ could have led to the enhancement of drought tolerance. Besides the fact that water deficit decreased the majority of chemical components in almond kernels, the grafting combination ‘Texas’/’GF 677’ can be grown in drought conditions without significant loss of kernel quality.