Genotype and year variability of the chemical composition of walnut oil of Moroccan seedlings from the high Atlas Mountains

Abstract

Protein and oil content, fatty acid composition and tocopherol concentration were determined for two years in the kernel of ten candidate walnut selections from the high Atlas Mountains in Morocco. Considerable variation between genotypes was found for all parameters. The ranges of protein content (11.58–14.5% of kernel dry weight, DW), oil content (54.4–67.48% of kernel DW), oleic (12.47–22.01% of total oil), linoleic (55.03–60.01%), linolenic (9.3–15.87%), palmitic (6.84–9.12%), and stearic (1.7–2.92%) acid percentages, γ-tocopherol (188.1–230.7 mg·kg -1 of oil), δ-tocopherol (23.3–43.4 mg·kg -1 ), and α-tocopherol (8.9–16.57 mg·kg -1 ) contents agreed with previous results obtained from other commercial walnut cultivars. The effect of year was significant for all the chemical components, except for oil content and palmitic acid percentage. Some genotypes showed high oil contents and consistently high values of γ-tocopherol in both years of study. The introduction of these genotypes as new cultivars by vegetative propagation may result in a an increase in quality of the walnuts from the high Atlas Mountains of Morocco, and as a seed source for forest walnut propagation in the same region.