Centuries-old generative reproduction, relatively favourable agro-ecological conditions, natural selection, and anthropogenic roles have significantly influenced the formation of a rich, heterogeneous population of common walnuts in Montenegro. This variability can be exploited by applying a positive selection of genotypes that would have good ecological adaptability and high economic value and that would not lag behind walnut varieties originating from other countries. The paper presents the results of studying 20 selected walnut genotypes from the continental part of Montenegro in a three-year period. Šeinovo variety and the Rasna selection were used as standard. The most important biological and pomological properties were investigated based on the international walnut descriptor. The basic criteria on which the selection approach was based were: late vegetation initiation, earlier date of end of vegetation, well kernel ratio, ease of kernel removal from the shell, shell texture that should be less rough, protecting the kernel, tasty kernel, light coloured kernel, and good chemical composition of the kernel. Genotypes had fruit weight between 8.43 and 13.84 g, kernel weight between 4.20 and 6.54 g, kernel ratio between 39.20 and 52.25%, oil content between 62.04 and 67.23%, and protein content between 13.91 and 19.04%. Most of the selected genotypes have the late time of leaf bud burst, and from that point of view, the BP44 and BP42 genotypes that the leafing on May 5 and 6 are especially interesting, due to avoidance of late frost. The walnut is adapted to the existing agro-ecological conditions over a long period of successful growth in this region, and most genotypes finish their vegetation earlier and are prepared to enter the period of winter dormancy. Genotypes BP09 and AN29 with their properties surpass the worldwide recognized Šeinovo, and in this region, highly valued selection Rasna. BP48 and BP50 genotypes also deserve attention due to the quality of the fruit.

Thousands of years of tradition of olive cultivation in Montenegro is witnessed with the ‘Old olive’ estimated to be more than 2000 years old. ‘Old olive’ draws attention to its genetic potential and the relation to the closest grown olive cultivars. Therefore, the aim of this paper was to give the basic description of ‘Old olive’ (through 20 morphological and 37 chemical properties) as well as to determine its DNA profile and to examine the closeness with major olive cultivar grown, cv. ‘Žutica’. The obtained data showed the differences between examined samples. ‘Old olive’ started flowering (27. May) more than 10 days later than cv. ‘Žutica’ (14. May), and began ripening 15 days later (20^th October and 5^th October, respectively). From 21 morphological parameters analysed all traits of fruit (weight 2.11g in ‘Old olive’ and 3.55g in cv. ‘Žutica’), and inflorescence density (6.39 versus 5.55) showed very significant and significant differences, respectively. The chemical properties also showed very significant differences in olive oil content in the fresh (11.28 versus 19.68%) and dry matter (27.97 versus 47.78%), and significant differences in the content of linolenic acid (0.76 versus 0.54g/100 of FA and of campesterol (3.4 versus 3.1%). Three out of eleven SSR markers (DCA05, DCA09, DCA16) distinguished obtained DNA fragments, and showed as important tool in differentiation of two samples. Further study of the ‘Old olive’ as a living memory of olive cultivation in Montenegro, should be to examine its relation with other ancient olive trees and local varieties.

Aim of study: One of the newly introduced olive varieties in Montenegro is the Spanish olive (Olea europaea L.) variety ‘Arbequina’. The aim of this work was to study the changes in the reproductive physiology of the cultivar 'Arbequina' in conditions of Montenegro. Area of study: Comparative experimental plots were established in two areas in Montenegro, the coastal region of Ulcinj and the inland region of Podgorica. Material and methods: The research was conducted at four experimental sites (UL1 and UL2 in Ulcinj; PG1 and PG2, in Podgorica) over four years. Flowering phenophases, inflorescence characteristics, and inflorescence architecture were assessed. Pollination trials consisted of open-pollination, self-pollination, and cross-pollination of ‘Arbequina’ with several olive varieties, resulting in an assessment of fruit set. Main results: A high level of fruit set (6.75%) in ‘Arbequina’ in open-pollination was recorded in the multi-varietal orchard (PG2). A much lower fruit set was found in the mono-varietal hedgerow orchards (0.75% in PG1 and 0.33% in UL2). The fruit set was very low in the mono-varietal orchards in self-pollination trials, ranging from 0.01% (PG1) to 0.06% (UL1). Research highlights: These results confirm that ‘Arbequina’ is a self-incompatible variety, which is crucial both for farmers in establishing new plantations and for scientists in future research. Some of the 11 olive varieties cross-pollinated with the ‘Arbequina’ variety displayed pollinating potential, which needs to be proven with paternity tests. Despite the differences between experimental sites and areas, ‘Arbequina’ exhibited high reproductive potential, confirmed by many perfect flowers.