Variability of chromosome number and morphology and gymnosperm improvement

The causes of monotypic and polytypic variability of the gymnosperm chromosome complex were studied. The development of karyogram and idiograms of the species should be applied in the aim of upgrading the breeding method and technique. The study of the chromosome variability depends on the knowledge on gene function at the level of chromosome and at the level of genome, i.e. at the supra-chromosome level

Variability of morphological characteristics of leaves and fruits of common hackberry (Celtis occidentalis L.) test trees from Sombor area

Two species of the genus Celtis L. are represented in the city of Sombor, of which the most numerous is Celtis occidentalis L., prevalent in parks and alleys, which became a symbol of the city, with its priceless social, economic and environmental value. Their present situation could be described as alarming. The paper presents the results of the analysis of morphological characteristics of leaves and fruits of common hackberry, investigated at the level of 15 test trees, in order to assess the genetic variability of the available gene pool in the tree alleys at Sombor area. Following parameters were analyzed: total leaf length, lamina width, petiole length, and lamina width at the left and right side from midrib, as well as drupe diameter and weight of 1000 fruits. The descriptive statistics, one-way analysis of variance, LSD test and cluster analysis were done. The largest leaves were recorded at trees 1, 5 and 11, and smallest at the trees 7, 9 and 13, wherein genotype 1 was distanced from the other test trees, on multiple characteristics. The highest average of drupes diameter were recorded at trees number 4, 12, and 3. The obtained results indicate a satisfactory degree of variability of the analyzed characteristics at the level of test trees, which provides a good basis for exploring and proper use of the genetic potential of this species, as well as for conservation of the available gene pool. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TP 31041: Forest plantations in order to increase forestation of Serbia