In the study on variability of common walnut, we applied, for the first time in Moldova, the principle of population. As a result, the limits and the level of variability of characters were determined. It was also assessed the agrobiological and selection potential of the local population. The proportion (part) of genotypic variability (ɳ2) in the general phenotypic variability, which gives the opportunity to assess the effectiveness of artificial selection, was determined on the basis of the analysis of variance. For such characters as the mass of the nut, the thickness of the shell, the proportion (ɳ2) is quite high – 60-80%, while for the mass and output of kernel, it is much lower – 24-37%. The probability of frequency, in the population, of forms with valuable characters was also determined. Thus, the output of kernel of 60% occurs with the probability of 1 : 120; the high resistance to marsonia (of 6 points) – 1 : 212; high and stable yield – 1 : 300; forms with high indices at a group of 7 agro-biological characters (with “quality index” 10) – 1 : 576. In the comparative study of variability of walnut in the primary genocentre (South Kyrgyzstan and Tajikistan) and Moldova, we have found that the composition of walnut forms in Moldova is almost the same as in the primary genocentre and the amplitude of variability of characters is greater than in the primary genocentre, which demonstrates the existence of a focus of the secondary genocentre in Moldova. This focus represents the genetic basis for the selection of new varieties of walnut. The population study of the local gene pool of walnut resulted in the selection of 10 valuable varieties, two of which – ′Codrene′ and ′Lunguieţe′ are homologated and six varieties are registered and submitted to State Commission for Variety Testing. All of the 6 varieties are distinguished by high and regular yields.  The production is rather uniform (coefficient of variation CV – 8-13), the trees are resistant to frost and to marsonia. Walnuts have an attractive appearance; the kernel is full, light coloured.  Indices of agro-biological characters     Nut mass, g Kernel mass, g Output of kernel, % Shell thickne ss, mm Yield, kg/tree CV Resista nce to frost,  points Resista nce to marsoni a, points Quality index De Vălcine ț 11,3±0, 63 6,0 53,1±0, 49 1,1 30 12,90 4,5 4,5 10,3 Surpriz 11,5±0, 64 6,3 54,5±0, 56 1,0 27 12,35 4,5 5,0 10,3 Dolna 9,9±0,7 1 5,2 52,5±0, 87 1,2 35 11,50 4,5 5,0 10,0 Nistren e 10,7±0, 66 5,5 51,2±0, 66 1,3 32 11,80 4,5 5,0 10,0 Micleuş ene 12,6±0, 33 6,2 49,1±0, 94 1,1 30 8,34 4,5 5,0 9,7 Chişină uiene 11,9±0, 42 6,0 50,4±0, 54 1,0 32 10,11 4,5 5,0 9,7