Geometrical Traits in Almond Fruit as Affected by Genotypic and Environmental Variations in Northern Morocco.

We investigated geometrical traits of almond nuts and its kernels in five major commercial almond cultivars: 'Ferraduel', 'Ferragnès', 'Fournat de Brézenaud', 'Marcona', and 'Tuono' at initial moisture content. Three different environments of northern Morocco, namely Aknoul, Bni Hadifa, and Tahar Souk, were considered for sampling. Geometrical determinations were performed both in nuts and kernels, and consisted of the nine following parameters: length (L), width (W), thickness (T), arithmetic mean diameter (D_a), geometric mean diameter (D_g), sphericity (Φ), volume (V), surface area (S_a) and projected area (P_a). ANOVA analyses showed that site, cultivar, and their interaction affected significantly all the parameters studied. L and Φ were genetically controlled, while T was environment-dependent for both nuts and kernels as well as D_g, V, S_a, P_a only for nuts. The rest of traits were equally determined by genotypic and environmental effects. Principal component analysis (PCA) explained about 97% and 89% of total variability in almond nuts and kernels, respectively and allowed a good discrimination among sites and cultivars. Among sites, Bni Hadifa favored a better expression of almost investigated traits while for cultivars; 'Marcona'' exhibited the highest scores for the majority of studied traits. Multiple regression models were developed for D_a, D_g, Φ, V, S_a, P_a as function of the three axial dimensions (L, W, T). For almond nuts, D_g, V, and S_a depended mainly on W. Moreover, Φ determined equally by L and T, while D_a and P_a were mostly dependent on L. As regards of almond kernels, L was the most consistent trait that determined variation in D_a, D_g, Φ, V, S_a, and P_a. [ABSTRACT FROM AUTHOR]