Relationship between Some Traits and Nut Production in Walnut Cultivars and Genotypes

Walnut is one of the most important nut crops in Iran. Because of its sexual propagation in Iran, the tree shows a high genetic diversity. In this study, the correlations between trunk cross-sectional area, scaffold cross area, crop density per trunk cross-sectional area and scaffold cross area, number of leaves and leaf area per nut, nut number to branch cross-sectional area, leaf number to branch cross-sectional area, leaf area to branch cross-sectional area and alternate bearing in eight terminal and lateral nutting genotypes were studied in walnut collection of Seed and Plant Improvement Institute of Iran in two years. Number of nuts to trunk cross sectional area and number of nuts to scaffold cross area were 1.68 (nuts/cm2) and 19.43 (nuts/m2), respectively. The average number of leaves and leaf area per nut were 4.42 (leaf/nut) and 1346.33 (cm2 leaf/nut), respectively. The lowest nut density (number of nut/cm2 branch cross sectional area) was found to be in genotype H1-1 (2.74) and the highest value was found in ‘Pedro’ (4.36). The correlation coefficient between nut density and leaf area per nut was -0.7. The highest alternate bearing was detected in ‘Hartley’ (15.38 %). This study showed that nut number and branch cross sectional area, nut number and branch leaf area, and branch leaf area and branch cross sectional area had very high correlations, and the polynomial regression model was appropriate for studying the relationship between the evaluated traits with high determination coefficients.