Characterization of walnut (Juglans regia L.) hybrid genotypes; fatty acid composition, biochemical properties and nutrient contents

This study was conducted to determine the protein, fat, mineral, fatty acid, and bioactive compound contents of 47 walnut hybrids obtained by intraspecies hybridization of G1, G2, and G3 walnut genotypes with Chandler, Mara & scedil; 18, and Pedro walnut cultivars. A wide variation was found between the hybrid walnut genotypes regarding the investigated properties. Among the hybrid genotypes, C1 had the highest bioactive compound content in terms of total flavonoids with 147.63 mg 100 g(-1), P4 had the highest antioxidant activity with 72.73 mmol 100 g(-1), and M13 had the highest total phenolic content with 1465.87 mg 100 g(-1). In addition, the highest oleic acid content was 23.23%, and polyunsaturated fatty acids (MUFA) content was 23.4%. The M15 had the highest protein content (18.06%) and total fat content (68.3%). Genotype P6 showed the highest results in terms of K (764.26 mg 100 g(-1)), P (764.26 mg 100 g(-1)), Fe (2.61 mg 100 g(-1)), PUFA (74.11%) and linoleic acid (63.74%). Similarly, the P15 genotype was found to be significant for fatty acids, with the highest values for myristric acid (0.07%), eicosenoic acid (1.164%), and eicosadienoic acid (0.069%). According to the principal component analysis, the eigenvalue for 10 principal components was above 1. It corresponded to 82.5% of the total variation, thus effectively revealing the variation among walnut genotypes for the investigated characteristics. These results indicate that most of the examined walnut genotypes are rich in minerals, fatty acids, and bioactive compounds. Therefore, these walnut hybrids with high nutritional value and health-important traits can be used as genetic material in walnut breeding programs and to develop new walnut cultivars.