Variability of some morphological traits of one-year old red oak, black walnut, birch and wild pear seedlings in the nurseries of Jastrebac region

Abstract

Five morphological and quantitative characteristics of one-year old seedlings of Red oak (Quercus rubra L), Black walnut (Juglans nigra L), Wild pear (Pyrus pygrowser Borkh) and Birch (Betula verrucosa Ehrh) were studied. The seedlings were produced and cultivated in the controlled conditions of the nursery in the region of Jastrebac, by the classical method. Aboveground seedling height, root collar diameter, root length, number of secondary roots and the leaf assimilation area were analysed. Intraspecific and interspecific variability of morphological features of the above species were assessed by the comparative analysis and statistical methods The comparative analysis shows the great individual variability of seedlings, which can indicate their genetic potential, adaptation to environment conditions, further spontaneous selection and the development in natural conditions. This justifies the need of the quality assessment and the first selection already in the nursery, in order to ensure the quality planting material and to reduce the risk of afforestation failure One-year old birch seedlings have the lowest average height (18.8 cm). Black walnut and Wild pear seedlings are approximately twice as high, and Red oak about 2.5 times higher. At the same time Red oak seedlings have for about one-fourth greater height than Black walnut, and for one-third greater height than Wild pear. Wild pear seedlings attain the averagely twice larger root collar diameter than Birch (2.8 cm), Red oak seedlings about 2.5 times larger diameter, and Black walnut 3.5 times larger diameter. Black walnut has a larger root collar diameter than Red oak for about one third, and almost twice larger than Wild pear. Birch, Red oak and Wild pear have almost twice longer root (1.8-1.9 times), Black walnut about 2.25 times longer. The total assimilation area of a Birch seedling is averagely 89.0 cm2. Compared to birch, wild pear has approximately double assimilation area per tree, Red oak 10 times larger, Black walnut even 14 times larger assimilation area The analysis of variance shows that the experiment is homogeneous in general, i.e. that variance within the group of the same species per all characteristics is not statistically significant at the level p>0.01. The statistically significant difference was found in the attained heights of one-year old seedlings of Red oak and Birch, as well as between them and other species, while there is no difference between Black walnut and Wild pear. All analysed species differ significantly in root collar diameter of one-year old seedlings. Black walnut and Birch differ significantly in root length, and also compared to other species. There are no statistically significant differences in root length between Red oak and Wild pear. All the analysed species differ statistically significantly per total assimilation area of one seedling .